To: Users From: Bob Supnik Subj: Simulator Usage, V2.3a Date: 1-Sep-97 COPYRIGHT NOTICE The following copyright notice applies to both the SIMH source and binary: Original code published in 1993-97, written by Robert M Supnik Portions Copyright (C) 1993-1997 Digital Equipment Corporation All Rights Reserved except as specified below. Permission is hereby granted to use, copy, modify, and distribute this software (or portions thereof) for any non-commercial purpose, without fee, subject to these conditions: (1) If any part of the source code for this software is distributed, then this copyright and no-warranty notice must be included unaltered; and any additions, deletions, or changes to the original files must be clearly indicated in accompanying documentation. (2) If only executable code is distributed, then the accompanying documentation must state that "this software is based in part on the original work of Robert M Supnik". (3) Permission for use of this software is granted only if the user accepts full responsibility for any undesirable consequences; the authors accept NO LIABILITY for damages of any kind. These conditions apply to any software derived from or based on this code, not just to the unmodified code. Permission is NOT granted for the use of any author's name or company name in advertising or publicity relating to this software or products derived from it. This memorandum documents the PDP-8, PDP-11, PDP-1, other 18b PDP, Nova, and IBM 1401 simulators. These simulators are freeware; commercial use is prohibited, and support is not available. The best way to fix problems or add features is to read and modify the sources yourself. Alternately, you can send Internet mail to bob.supnik@digital.com, but responses are not guaranteed. The simulators use a common command interface. The memorandum first describes the common features of the command interface and then provides information on each of the individual simulators. 1. Compiling And Running A Simulator The simulators have been tested on VAX VMS, Alpha VMS, Alpha UNIX, Intel FreeBSD and Intel LINUX; a port to Windows 95 and Windows NT is in progress but lacks terminal emulation code. Porting to other environments will require changes to the operating system dependent code in scp_tty.c. To compile the simulators on VMS, use these commands (note that separate compilations are required for each of the 18b PDP's): $ cc pdp8_*.c,scp.c,scp_tty.c ! PDP-8 $ link/exec=pdp8 pdp8_*.obj,scp.obj,scp_tty.obj $ cc pdp11_*.c,scp.c,scp_tty.c ! PDP-11 $ link/exec=pdp11 pdp11_*.obj,scp.obj,scp_tty.obj $ cc nova_*.c,scp.c,scp_tty.c ! Nova $ link/exec=nova nova_*.obj,scp.obj,scp_tty.obj $ cc pdp1_*.c,scp.c,scp_tty.c ! PDP-1 $ link/exec=pdp1 pdp1_*.obj,scp.obj,scp_tty.obj $ cc/define=PDP{4,7,9,15} pdp18b_*.c,scp.c,scp_tty.c $ link/exec=pdp{4,7,9,15} pdp18b_*.obj,scp.obj,scp_tty.obj $ cc i1401_*.c,scp.c,scp_tty.c ! IBM 1401 $ link/exec=i1401 i1401_*.obj,scp.obj,scp_tty.obj On version of VMS prior to 6.2, the simulators must then be defined as foreign commands so that they can be started by name. To compile the simulators on Alpha UNIX or any UNIX variant which supports the POSIX compliant TERMIOS interface, use the following commands (note that separate compilations are required for each of the 18b PDP's): % cc pdp8_*.c scp*.c -lm -o pdp8 % cc pdp11_*.c scp*.c -lm -o pdp11 % cc nova_*.c scp*.c -lm -o nova % cc pdp1_*.c scp*.c -o pdp1 % cc -DPDP{4,7,9,15} pdp18b_*.c scp*.c -lm -o pdp{4,7,9,15} % cc i1401_*.c scp*.c -o i1401 These commands should work with most UNIX variants. If your UNIX only supports the old BSD terminal interface, add -DBSDTTY to each command. To start the simulator, simply type its name. The simulator takes one optional argument, a startup command file. If specified, this file should contain a series of non-interactive simulator commands, one per line. These command can be used to set up standard parameters, for example, disk sizes. % pdp8 (cr) or % pdp11 (cr) or % nova (cr) or % pdp1 (cr) or % pdp{4,7,9,15} (cr) or % i1401 (cr) The simulator types out its name and version, executes the commands in the startup file, if any, and then prompts for input with sim> 2. Simulator Conventions A simulator consists of a series of devices, the first of which is always the CPU. A device consists of named registers and one or more numbered units. Registers correspond to device state, units to device address spaces. Thus, the CPU device might have registers like PC, ION, etc, and a unit corresponding to main memory; a disk device might have registers like BUSY, DONE, etc, and units corresponding to individual disk drives. Except for main memory, device address spaces are simulated as unstructured binary disk files in the host file system. The SHOW CONFIG command displays the simulator configuration. A simulator keeps time in terms of arbitrary units, usually one time unit per instruction executed. Simulated events (such as completion of I/O) are scheduled at some number of time units in the future. The simulator executes synchronously, invoking event processors when simulated events are scheduled to occur. Even asynchronous events, like keyboard input, are handled by polling at synchronous intervals. The SHOW QUEUE command displays the simulator event queue. 3. Commands 3.1 Loading Programs The LOAD command (abbreviation LO) loads a file in binary paper-tape loader format: sim> load (cr) 3.2 Saving and Restoring State The SAVE command (abbreviation SA) save the complete state of the simulator to a file. This includes the contents of main memory and all registers, and the I/O connections of devices: sim> save (cr) The RESTORE command (abbreviation REST, alternately GET) restores a previously saved simulator state: sim> restore (cr) Note: SAVE file format compresses zeroes to minimize file size. 3.3 Resetting Devices The RESET command (abbreviation RE) resets a device or the entire simulator to a predefined condition: sim> RESET(cr) -- reset all devices sim> RESET ALL(cr) -- reset all devices sim> RESET (cr) -- reset specified device Typically, RESET stops any in-progress I/O operation, clears any interrupt request, and returns the device to a quiescent state. It does not clear main memory or affect I/O connections. 3.4 Connecting and Disconnecting Devices Except for main memory, simulated unit address spaces are simulated as unstructured binary disk files in the host file system. Before using a simulated unit the user must specify the file to be accessed by that unit. The ATTACH (abbreviation AT) command associates a unit and a file: sim> ATTACH (cr) If the file does not exist, it is created, and an appropriate message is printed. The DETACH (abbreviation DET) command breaks the association between a unit and a file and closes the file: sim> DETACH ALL(cr) -- detach all units sim> DETACH (cr) -- detach specified unit The EXIT command performs an automatic DETACH ALL. 3.5 Examining and Changing State There are four commands to examine and change state: EXAMINE (abbreviated E) examines state DEPOSIT (abbreviated D) changes state IEXAMINE (interactive examine, abbreviated IE) examines state and allows the user to interactively change it IDEPOSIT (interactive deposit, abbreviated ID) allows the user to interactively change state All four commands take the form command {-switches} {{}} Deposit must also include a deposit value at the end of the command. The examine and deposit commands can work on the address space of any unit. If no device is specified, the CPU (main memory) is selected; if a device but no unit is specified, unit 0 of the specified device is selected. The "state list" consists of one or more of the following, separated by commas: register the specified register register1-register2 all the registers starting at register1 up to and including register2 address the specified location address1-address2 all locations starting at address1 up to and including address2 STATE all registers in the device ALL all locations in the unit Switches can be used to control the format of display information: -a display as ASCII -c display as character string -m display as instruction mnemonics The simulators typically accept symbolic input (see simulator sections). Examples: sim> ex 1000-1100 -- examine 1100:1100 sim> de PC 1040 -- set PC to 1040 sim> ie 40-50 -- interactively examine 40:50 sim> ex rx0 50060 -- examine 50060, RX unit 0 sim> de all 0 -- set main memory to 0 Note: to terminate an interactive command, simply type a bad value (eg, XXX) when input is requested. 3.6 Running Programs The RUN command (abbreviated RU) resets all devices, deposits its argument (if given) in the PC, and starts execution. If no argument is given, execution starts at the current PC. The GO command does NOT reset devices, deposits its argument (if given) in the PC, and starts execution. If no argument is given, execution starts at the current PC. The CONT command (abbreviated CO) does NOT reset devices and resumes execution at the current PC. The STEP command (abbreviated S) resumes execution at the current PC for the number of instructions given by its argument. If no argument is supplied, one instruction is executed. The BOOT command (abbreviated BO) bootstraps the device and unit given by its argument. If no unit is supplied, unit 0 is bootstrapped. The specified unit must be attached to a file. 3.7 Stopping Programs Programs run until the simulator detects an error or stop condition, or until the user forces a stop condition. 3.7.1 Simulator Detected Stop Conditions These simulator-detected conditions stop simulation: - HALT instruction. If a HALT instruction is decoded, simulation stops. - Breakpoint. The IBKPT register provides a single virtual address breakpoint. If the PC matches the contents of the IBKPT register, simulation stops. The breakpoint is automatically disabled for the next instruction execution. - I/O error. If an I/O error occurs during simulation of an I/O operation, and the device stop-on-I/O-error flag is set, simulation usually stops. - Processor condition. Certain processor conditions can stop simulation; these are described with the individual simulators. 3.7.2 User Specified Stop Conditions Typing the interrupt character stops simulation. The interrupt character is defined by the WRU (where are you) register and is initially set to 005 (^E). 3.8 Setting Device Parameters The SET command (abbreviated SE) changes the status of a device parameter: sim> SET The parameters are simulator and device specific. Disk drives, for example, can usually be set write ENABLED or write LOCKED; if a device supports multiple drive types, the SET command can be used to specify the drive type. 3.9 Displaying Parameters and Status The SHOW CONFIGURATION command shows the simulator configuration and the status of all simulated I/O devices. The SHOW command shows the status of the named simulated I/O device. The SHOW QUEUE command shows the state of the simulator event queue. Times are in "simulation units", typically one unit per instruction execution, relative to the current simulation time. The SHOW TIME command shows the number of time units elapsed since the last RUN command. 3.10 Altering the Simulated Configuration In devices with multiple units, the REMOVE command removes the specified unit from the configuration. Once removed, a unit cannot be manipulated in any way until it is added back to the configuration. ADD adds back a unit that had been removed from the configuration. 3.11 Exiting The Simulator EXIT (synonyms QUIT and BYE) returns control to the operating system. 4. PDP-8 Features The PDP-8 simulator is configured as follows: device simulates name(s) CPU PDP-8/E CPU with 32KW of memory - KE8E extended arithmetic element (EAE) - KM8E memory management and timeshare control PTR,PTP PC8E paper tape reader/punch TTI,TTO KL8E console terminal LPT LE8E line printer CLK DK8E line frequency clock (also PDP-8/A compatible) RK RK8E/RK05 cartridge disk controller with four drives RF RF08/RS08 fixed head disk controller with four platters RX RX8E/RX01 floppy disk controller with two drives MT TM8E/TU10 magnetic tape controller with eight drives The PDP-8 simulator implements one unique stop condition: if an undefined instruction (unimplemented IOT or OPR) is decoded, and register STOP_INST is set, the simulator halts. 4.1 CPU The only CPU options are the presence of the EAE and the size of main memory; the memory extension and time-share control is always included, even if memory size is 4K. SET CPU EAE enable EAE SET CPU NOEAE disable EAE SET CPU 4K set memory size = 4K SET CPU 8K set memory size = 8K SET CPU 12K set memory size = 12K SET CPU 16K set memory size = 16K SET CPU 20K set memory size = 20K SET CPU 24K set memory size = 24K SET CPU 28K set memory size = 28K SET CPU 32K set memory size = 32K If memory size is being reduced, and the memory being truncated contains non-zero data, the simulator asks for confirmation. Data in the truncated portion of memory is lost. Initial memory size is 32K. CPU registers include the visible state of the processor as well as the control registers for the interrupt system. name size comments PC 15 program counter, including IF as high 3 bits AC 12 accumulator MQ 12 multiplier-quotient L 1 link SR 12 front panel switches IF 3 instruction field DF 3 data field IB 3 instruction field buffer SF 7 save field UF 1 user mode flag UB 1 user mode buffer SC 5 EAE shift counter GTF 1 EAE greater than flag EMODE 1 EAE mode (0 = A, 1 = B) ION 1 interrupt enable ION_DELAY 1 interrupt enable delay for ION CIF_DELAY 1 interrupt enable delay for CIF PWR_INT 1 power fail interrupt UF_INT 1 user mode violation interrupt INT 15 interrupt pending flags DONE 15 device done flags ENABLE 15 device interrupt enable flags OLDPC 15 PC prior to last JMP, JMS, or interrupt STOP_INST 1 stop on undefined instruction BREAK 16 breakpoint address (177777 to disable) WRU 8 interrupt character 4.2 Programmed I/O Devices (PTR, PTP, TTI, TTO, CLK, LPT) The paper tape reader (PTR), paper tape punch (PTP), and line printer (LPT) read data from or write data to disk files. The POS register specifies the number of the next data item to be read or written. Thus, by changing POS, the user can backspace or advance these devices. The teletype reads and writes to the controlling console port. The keyboard has one option, UC; when set, it automatically converts lower case input to upper case. This is required by OS/8 and is on by default. The programmed I/O devices typically implement these registers: name size comments BUF 8 last data item processed INT 1 interrupt pending flag DONE 1 device done flag ENABLE 1 interrupt enable flag TIME 24 time from I/O initiation to interrupt (for keyboard, polling interval) POS 31 position in the input or output file STOP_IOE 1 stop on I/O error For the serial devices, error handling is as follows: type error STOP_IOE processed as in,out not attached 1 report error and stop 0 out of tape or paper in end of file 1 report error and stop 0 out of tape or paper in,out OS I/O error x report error and stop 4.3 RK8E/RK05 RK8E options include the ability to make units write enabled or write locked: SET RKn LOCKED set unit n write locked SET RKn ENABLED set unit n write enabled Units can also be REMOVEd or ADDed to the configuration. The RK8E implements these registers: name size comments STA 12 status DA 12 disk address MA 12 current memory address CMD 12 disk command BUSY 1 control busy flag INT 1 interrupt pending flag STIME 24 seek time, per cylinder RTIME 24 rotational delay STOP_IOE 1 stop on I/O error Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready end of file x assume rest of disk is zero OS I/O error x report error and stop 4.4 RX8E/RX01 RX8E options include the ability to set units write enabled or write locked: SET RXn LOCKED set unit n write locked SET RXn ENABLED set unit n write enabled The RX8E implements these registers: name size comments RXCS 12 status RXDB 12 data buffer RXES 8 error status RXTA 8 current track RXSA 8 current sector STAPTR 3 controller state BUFPTR 3 buffer pointer INT 1 interrupt pending flag DONE 1 device done flag ENABLE 1 interrupt enable flag TR 1 transfer ready flag ERR 1 error flag CTIME 24 command completion time STIME 24 seek time, per track XTIME 24 transfer ready delay STOP_IOE 1 stop on I/O error Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready RX01 data files are buffered in memory; therefore, end of file and OS I/O errors cannot occur. 4.5 RF08/RS08 The RF08 implements these registers: name size comments STA 12 status DA 20 current disk address MA 12 memory address (in memory) WC 12 word count (in memory) WLK 32 write lock switches INT 1 interrupt pending flag DONE 1 device done flag TIME 24 rotational delay, per word BURST 1 burst flag STOP_IOE 1 stop on I/O error The RF08 is a three-cycle data break device. If BURST = 0, word transfers are scheduled individually; if BURST = 1, the entire transfer occurs in a single data break. Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready RF08 data files are buffered in memory; therefore, end of file and OS I/O errors cannot occur. 4.6 Magnetic Tape (MT) Magnetic tape options include the ability to make units write enabled or or write locked. SET MTn LOCKED set unit n write locked SET MTn ENABLED set unit n write enabled Units can also be REMOVEd or ADDed to the configuration. The magnetic tape controller implements these registers: name size comments CMD 12 command FNC 12 function CA 12 memory address WC 12 word count DB 12 data buffer STA 12 main status STA2 6 secondary status DONE 1 device done flag INT 1 interrupt pending flag STOP_IOE 1 stop on I/O error TIME 24 record delay UST0..7 24 unit status, units 0..n POS0..7 31 position, units 0..n Error handling is as follows: error processed as not attached tape not ready end of file (read or space) end of physical tape (write) ignored OS I/O error report error and stop 4.7 Symbolic Display and Input The PDP-8 simulator implements symbolic display and input. Display is controlled by command line switches: -a display as ASCII character -c display as (sixbit) character string -m display instruction mnemonics Input parsing is controlled by the first character typed in or by command line switches: ' or -a ASCII character " or -c two character sixbit string alphabetic instruction mnemonic numeric octal number Instruction input uses standard PDP-8 assembler syntax. There are four instruction classes: memory reference, IOT, field change, and operate. Memory reference instructions have the format memref {I} {C/Z} address where I signifies indirect, C a current page reference, and Z a zero page reference. The address is an octal number in the range 0 - 07777; if C or Z is specified, the address is a page offset in the range 0 - 177. Normally, C is not needed; the simulator figures out from the address what mode to use. However, when referencing memory outside the CPU (eg, disks), there is no valid PC, and C must be used to specify current page addressing. IOT instructions consist of single mnemonics, eg, KRB, TLS. IOT instructions may be or'd together iot iot iot... The simulator does not check the legality of the proposed combination. IOT's for which there is no opcode may be specified as IOT n, where n is an octal number in the range 0 - 0777. Field change instructions (CIF, CDF) have the format fldchg field where field is an octal number in the range 0 - 7. Field change instructions may be or'd together. Operate instructions have the format opr opr opr... The simulator does not check the legality of the proposed combination. EAE mode A and B mnemonics may be specified regardless of the EAE mode. The operands for MUY and DVI must be deposited explicitly. 5. PDP-11 Features The PDP-11 simulator is configured as follows: device simulates name(s) CPU J-11 CPU with 256KB of memory - FP11 floating point unit (FPA) PTR,PTP PC11 paper tape reader/punch TTI,TTO DL11 console terminal LPT LP11 line printer CLK line frequency clock RK RK11/RK05 cartridge disk controller with eight drives RL RLV12/RL01(2) cartridge disk controller with four drives RP RM02/03/05/80, RP04/05/06/07 Massbus style controller with eight drives RX RX11/RX01 floppy disk controller with two drives TM TM11/TU10 magnetic tape controller with eight drives The PDP-11 simulator implements several unique stop conditions: - abort during exception vector fetch, and register STOP_VEC is set - abort during exception stack push, and register STOP_SPA is set - trap condition 'n' occurs, and register STOP_TRAP is set - wait state entered, and no I/O operations outstanding (ie, no interrupt can ever occur) 5.1 CPU The only CPU options are disabling of 22b addressing and the size of main memory. SET CPU 18B disable 22b addressing SET CPU 22B enable 22b addressing SET CPU 16K set memory size = 16KB SET CPU 32K set memory size = 32KB SET CPU 48K set memory size = 48KB SET CPU 64K set memory size = 64KB SET CPU 96K set memory size = 96KB SET CPU 128K set memory size = 128KB SET CPU 192K set memory size = 192KB SET CPU 256K set memory size = 256KB SET CPU 384K set memory size = 384KB SET CPU 512K set memory size = 512KB SET CPU 768K set memory size = 768KB SET CPU 1024K (or 1M) set memory size = 1024KB SET CPU 2048K (or 2M) set memory size = 2048KB SET CPU 3072K (or 3M) set memory size = 3072KB SET CPU 4096K (or 4M) set memory size = 4096KB If memory size is being reduced, and the memory being truncated contains non-zero data, the simulator asks for confirmation. Data in the truncated portion of memory is lost. Initial memory size is 256KB. These switches are recognized when examining or depositing in CPU memory: -v interpret address as virtual -d if mem mgt enabled, force data space -k if mem mgt enabled, force kernel mode -s if mem mgt enabled, force supervisor mode -u if mem mgt enabled, force user mode -p if mem mgt enabled, force previous mode CPU registers include the visible state of the processor as well as the control registers for the interrupt system. name size comments PC 16 program counter R0..R5 16 R0..R5, first register set R10..R15 16 R0..R5, second register set KSP 16 kernel stack pointer SSP 16 supervisor stack pointer USP 16 user stack pointer PSW 16 processor status word CM 2 current mode, PSW<15:14> PM 2 previous mode, PSW<13:12> RS 2 register set, PSW<11> IPL 3 interrupt priority level, PSW<7:5> T 1 trace bit, PSW<4> N 1 negative flag, PSW<3> Z 1 zero flag, PSW<2> V 1 overflow flag, PSW<1> C 1 carry flag, PSW<0> SR 16 front panel switches DR 16 front panel display MEMERR 16 memory error register CCR 16 cache control register MAINT 16 maintenance register HITMISS 16 hit/miss register CPUERR 16 CPU error register PIRQ 16 programmed interrupt requests FAC0H..FAC5H 32 FAC0..FAC5, high 32 bits FAC0L..FAC5L 32 FAC0..FAC5, low 32 bits FPS 16 floating point status FEA 16 floating exception address FEC 4 floating exception code MMR0..3 16 memory management registers 0..3 {K/S/U}{I/D}{PAR/PDR}{0..7} 16 memory management registers INT 32 interrupt pending flags TRAP 18 trap pending flags WAIT 0 wait state flag WAIT_ENABLE 0 wait state enable flag STOP_TRAPS 18 stop on trap flags STOP_VECA 1 stop on read abort in trap or interrupt STOP_SPA 1 stop on stack push abort in trap or interrupt OLDPC 16 PC prior to last JMP, JMS, or interrupt BREAK 16 breakpoint address (1 to disable) WRU 8 interrupt character 5.2 Programmed I/O Devices (PTR, PTP, TTI, TTO, CLK, LPT) The paper tape reader (PTR), paper tape punch (PTP), and line printer (LPT) read data from or write data to disk files. The POS register specifies the number of the next data item to be read or written. Thus, by changing POS, the user can backspace or advance these devices. The programmed I/O devices typically implement these registers: name size comments BUF 8 last data item processed CSR 16 control/status register INT 1 interrupt pending flag ERR 1 error flag (CSR<15>) DONE 1 device done flag (CSR<7>) IE 1 interrupt enable flag (CSR<6>) TIME 24 time from I/O initiation to interrupt (for keyboard, polling interval) POS 31 position in the input or output file STOP_IOE 1 stop on I/O error For the serial devices, error handling is as follows: type error STOP_IOE processed as in,out not attached 1 report error and stop 0 out of tape or paper in end of file 1 report error and stop 0 out of tape or paper in,out OS I/O error x report error and stop 5.3 RK11/RK05 RK11 options include the ability to make units write enabled or write locked: SET RKn LOCKED set unit n write locked SET RKn ENABLED set unit n write enabled Units can also be REMOVEd or ADDed to the configuration. The RK11 implements these registers: name size comments RKCS 16 control/status RKDA 16 disk address RKBA 16 memory address RKWC 16 word count RKDS 16 drive status RKER 16 error status INTQ 9 interrupt queue DRVN 3 number of last selected drive INT 1 interrupt pending flag ERR 1 error flag (CSR<15>) DONE 1 device done flag (CSR<7>) IE 1 interrupt enable flag (CSR<6>) INT 1 interrupt pending flag STIME 24 seek time, per cylinder RTIME 24 rotational delay STOP_IOE 1 stop on I/O error Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready end of file x assume rest of disk is zero OS I/O error x report error and stop 5.4 RX11/RX01 RX11 options include the ability to make units write enabled or write locked: SET RXn LOCKED set unit n write locked SET RXn ENABLED set unit n write enabled The RX11 implements these registers: name size comments RXCS 12 status RXDB 8 data buffer RXES 8 error status RXERR 8 error code RXTA 8 current track RXSA 8 current sector STAPTR 3 controller state BUFPTR 3 buffer pointer INT 1 interrupt pending flag ERR 1 error flag (CSR<15>) TR 1 transfer ready flag (CSR<7>) IE 1 interrupt enable flag (CSR<6>) DONE 1 device done flag (CSR<5>) CTIME 24 command completion time STIME 24 seek time, per track XTIME 24 transfer ready delay STOP_IOE 1 stop on I/O error Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready RX01 data files are buffered in memory; therefore, end of file and OS I/O errors cannot occur. 5.5 RL11(V12)/RL01,RL02 RL11 options include the ability to set units write enabled or write locked, and to set the drive size to RL01, RL02, or autosize: SET RLn LOCKED set unit n write locked SET RLn ENABLED set unit n write enabled SET RLn RL01 set size to RL01 SET RLn RL02 set size to RL02 SET RLn AUTOSIZE set size based on file size at attach The size options can be used only when a unit is not attached to a file. Units can also be REMOVEd or ADDed to the configuration. The RL11 implements these registers: name size comments RLCS 16 control/status RLDA 16 disk address RLBA 16 memory address RLBAE 6 memory address extension (RLV12) RLMP..RLMP2 16 multipurpose register queue INT 1 interrupt pending flag ERR 1 error flag (CSR<15>) DONE 1 device done flag (CSR<7>) IE 1 interrupt enable flag (CSR<6>) STIME 24 seek time, per cylinder RTIME 24 rotational delay STOP_IOE 1 stop on I/O error Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready end of file x assume rest of disk is zero OS I/O error x report error and stop 5.6 RM02/03/05/80, RP04/05/06/07 The RP controller implements a "Massbus style" 22b direct interface for large disk drives. It is more abstract than other device simulators, with just enough detail to run operating system drivers. In addition, the RP controller conflates the details of the RM series controllers with the RP series controllers, although there were detailed differences. RP options include the ability to set units write enabled or write locked, and to set the drive size to one of seven disk types, or autosize: SET RPn LOCKED set unit n write locked SET RPn ENABLED set unit n write enabled SET RPn RM03 set size to RM03 SET RPn RM05 set size to RM05 SET RPn RM80 set size to RM80 SET RPn RP04 set size to RP04 SET RPn RP06 set size to RP06 SET RPn RP07 set size to RP07 SET RPn AUTOSIZE set size based on file size at attach The size options can be used only when a unit is not attached to a file. Units can also be REMOVEd or ADDed to the configuration. The RP controller implements these registers: name size comments RPCS1 16 control/status 1 RPCS2 16 control/status 2 RPCS3 16 control/status 3 RPWC 16 word count RPBA 16 bus address RPBAE 6 bus address extension RPDA 16 desired surface, sector RPDC 8 desired cylinder RPOF 16 offset RPDS0..7 16 drive status, drives 0-7 RPDE0..7 16 drive error, drives 0-7 RPER2 16 error status 2 RPER3 16 error status 3 RPDB 16 data buffer RPMR 16 maintenance register INT 1 interrupt pending flag SC 1 special condition (CSR1<15>) DONE 1 device done flag (CSR1<7>) IE 1 interrupt enable flag (CSR1<6>) STIME 24 seek time, per cylinder RTIME 24 rotational delay STOP_IOE 1 stop on I/O error Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready end of file x assume rest of disk is zero OS I/O error x report error and stop 5.7 Magnetic Tape (TM) Magnetic tape options include the ability to make units write enabled or or write locked. SET TMn LOCKED set unit n write locked SET TMn ENABLED set unit n write enabled Units can also be REMOVEd or ADDed to the configuration. The magnetic tape controller implements these registers: name size comments MTS 16 status MTC 16 command MTCMA 16 memory address MTBRC 16 byte/record count INT 1 interrupt pending flag ERR 1 error flag DONE 1 device done flag IE 1 interrupt enable flag STOP_IOE 1 stop on I/O error TIME 24 delay UST0..7 16 unit status, units 0..n POS0..7 31 position, units 0..n Error handling is as follows: error processed as not attached tape not ready end of file (read or space) end of physical tape (write) ignored OS I/O error report error and stop 5.8 Symbolic Display and Input The PDP-11 simulator implements symbolic display and input. Display is controlled by command line switches: -a display as ASCII character -c display as two character ASCII string -m display instruction mnemonics Input parsing is controlled by the first character typed in or by command line switches: ' or -a ASCII character " or -c two character ASCII string alphabetic instruction mnemonic numeric octal number Instruction input uses standard PDP-11 assembler syntax. There are sixteen instruction classes: class operands examples comments no operands none HALT, RESET 3b literal literal, 0 - 7 SPL 6b literal literal, 0 - 077 MARK 8b literal literal, 0 - 0377 EMT, TRAP register register RTS sop specifier SWAB, CLR, ASL reg-sop register, specifier JSR, XOR, MUL fop flt specifier ABSf, NEGf ac-fop flt reg, flt specifier LDf, MULf ac-sop flt reg, specifier LDEXP, STEXP ac-moded sop flt reg, specifier LDCif, STCfi dop specifier, specifier MOV, ADD, BIC cond branch address BR, BCC, BNE sob register, address SOB cc clear cc clear instructions CLC, CLV, CLZ, CLN combinable cc set cc set instructions SEC, SEV, SEZ, SEN combinable For floating point opcodes, F and D variants, and I and L variants, may be specified regardless of the state of FPS. The syntax for specifiers is as follows: syntax specifier displacement comments Rn 0n - Fn 0n - only in flt reg classes (Rn) 1n - @(Rn) 7n 0 equivalent to @0(Rn) (Rn)+ 2n - @(Rn)+ 3n - -(Rn) 4n - @-(Rn) 5n - {+/-}d(Rn) 6n {+/-}d @{+/-}d(Rn) 7n {+/-}d #n 27 n @#n 37 n .+/-n 67 +/-n - 4 @.+/-n 77 +/-n - 4 {+/-}n 67 {+/-}n - PC - 4 if on disk, 37 and n @{+/-}n 77 {+/-}n - PC - 4 if on disk, invalid 6. Nova Features The Nova simulator is configured as follows: device simulates name(s) CPU Nova CPU with 32KW of memory - hardware multiply/divide PTR,PTP paper tape reader/punch TTI,TTO console terminal LPT line printer CLK real-time clock DK head-per-track disk controller DP moving head disk controller with four drives MT magnetic tape controller with eight drives The Nova simulator implements these unique stop conditions: - reference to undefined I/O device, and STOP_DEV is set - more than INDMAX indirect addresses are detected during an interrupt - more than INDMAX indirect addresses are detected during memory reference address decoding 6.1 CPU The only CPU options are the presence of the multiply/divide instructions and the size of main memory. SET CPU MDV enable multiply/divide SET CPU NOMDV disable multiply/divide SET CPU 4K set memory size = 4K SET CPU 8K set memory size = 8K SET CPU 12K set memory size = 12K SET CPU 16K set memory size = 16K SET CPU 20K set memory size = 20K SET CPU 24K set memory size = 24K SET CPU 28K set memory size = 28K SET CPU 32K set memory size = 32K If memory size is being reduced, and the memory being truncated contains non-zero data, the simulator asks for confirmation. Data in the truncated portion of memory is lost. Initial memory size is 32K. CPU registers include the visible state of the processor as well as the control registers for the interrupt system. name size comments PC 15 program counter AC0..AC3 16 accumulators 0..3 C 1 carry SR 16 front panel switches PI 16 priority interrupt mask ION 1 interrupt enable ION_DELAY 1 interrupt enable delay for ION PWR 1 power fail interrupt INT 15 interrupt pending flags BUSY 15 device busy flags DONE 15 device done flags DISABLE 15 device interrupt disable flags STOP_DEV 1 stop on undefined IOT INDMAX 15 maximum number of nested indirects OLDPC 15 PC prior to last JMP, JMS, or interrupt BREAK 16 breakpoint address (177777 to disable) WRU 8 interrupt character 6.2 Programmed I/O Devices (PTR, PTP, TTI, TTO, CLK, LPT) The paper tape reader (PTR), paper tape punch (PTP), and line printer (LPT) read data from or write data to disk files. The POS register specifies the number of the next data item to be read or written. Thus, by changing POS, the user can backspace or advance these devices. The terminal reads and writes to the controlling console port. Terminal options include the ability to set limited Dasher compatibility mode or normal mode: SET TTI ANSI normal mode SET TTI DASHER Dasher mode SET TTO ANSI normal mode SET TTO DASHER Dasher mode Setting either TTI or TTO changes both devices. In Dasher mode, carriage return is changed to newline on input, and ^X is changed to backspace. The programmed I/O devices typically implement these registers: name size comments BUF 8 last data item processed BUSY 1 device busy flag DONE 1 device done flag DISABLE 1 interrupt disable flag INT 1 interrupt pending flag TIME 24 time from I/O initiation to interrupt (for keyboard, polling interval) POS 31 position in the input or output file STOP_IOE 1 stop on I/O error For the serial devices, error handling is as follows: type error STOP_IOE processed as in,out not attached 1 report error and stop 0 out of tape or paper in end of file 1 report error and stop 0 out of tape or paper in,out OS I/O error x report error and stop 6.3 Fixed Head Disk (DK) The fixed head disk controller implements these registers: name size comments STAT 16 status DA 16 disk address MA 16 memory address BUSY 1 device busy flag DONE 1 device done flag DISABLE 1 device disable flag INT 1 interrupt pending flag WLK 8 write lock switches TIME 24 rotational delay, per sector STOP_IOE 1 stop on I/O error Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready Fixed head disk data files are buffered in memory; therefore, end of file and OS I/O errors cannot occur. 6.4 Moving Head Disk (DP) Moving head disk options include the ability to make units write enabled or write locked, and to select the type of drive: SET DPn LOCKED set unit n write locked SET DPn ENABLED set unit n write enabled SET DPn FLOPPY set unit n to floppy disk SET DPn D31 set unit n to Diablo 31 SET DPn D44 set unit n to Diablo 44 SET DPn C111 set unit n to Century 111 SET DPn C114 set unit n to Century 114 Units can also be REMOVEd or ADDed to the configuration. All drives have 256 16b words per sector. The other disk parameters are: drive cylinders surfaces sectors size (MW) DG models floppy 77 1 8 .158 6038 D31 203 2 12 1.247 4047, 4237, 4238 D44 408 4 12 5.014 4234, 6045 C111 203 10 6 3.118 4048 C114 203 20 12 12.472 4057, 2314 The moving head disk controller implements these registers: name size comments FCCY 16 flags, command, cylinder USSC 16 unit, surface, sector, count STAT 16 status MA 16 memory address BUSY 1 device busy flag DONE 1 device done flag DISABLE 1 interrupt disable flag INT 1 interrupt pending flag STIME 24 seek time, per cylinder RTIME 24 rotational delay Error handling is as follows: error processed as not attached disk not ready end of file assume rest of disk is zero OS I/O error report error and stop 6.5 Magnetic Tape (MT) Magnetic tape options include the ability to make units write enabled or or write locked. SET MTn LOCKED set unit n write locked SET MTn ENABLED set unit n write enabled Units can also be REMOVEd or ADDed to the configuration. The magnetic tape controller implements these registers: name size comments CU 16 command, unit MA 16 memory address WC 16 word count STA1 16 status word 1 STA2 16 status word 2 EP 1 extended polling mode (not supported) BUSY 1 device busy flag DONE 1 device done flag DISABLE 1 interrupt disable flag INT 1 interrupt pending flag STOP_IOE 1 stop on I/O error CTIME 24 controller delay RTIME 24 record delay UST0..7 32 unit status, units 0..n POS0..7 31 position, units 0..n Error handling is as follows: error processed as not attached tape not ready end of file (read or space) end of physical tape (write) ignored OS I/O error report error and stop 6.6 Symbolic Display and Input The Nova simulator implements symbolic display and input. Display is controlled by command line switches: -a display as ASCII character -c display as two character ASCII string -m display instruction mnemonics Input parsing is controlled by the first character typed in or by command line switches: ' or -a ASCII character " or -c two character ASCII string alphabetic instruction mnemonic numeric octal number Instruction input uses standard Nova assembler syntax. There are three instruction classes: memory reference, IOT, and operate. Memory reference instructions have the format memref {ac,}{@}address{,index} LDA and STA require an initial register; ISZ, DSZ, JSR, and JMP do not. The syntax for addresses and indices is as follows: syntax mode displacement comments 0 <= n < 0400 0 n {+/-}n >= 0400 1 {+/-}n - PC must be in range [-200, 177] invalid on disk .+/-n 1 {+/-}n must be in range [-200, 177] {+/-}n,2 2 {+/-}n must be in range [-200, 177] {+/-}n,3 3 {+/-}n must be in range [-200, 177] IOT instructions have one of four formats syntax example iot HALT iot reg INTA iot device SKPDN iot reg,device DOAS Devices may be specified as mnemonics or as numbers in the range 0 - 077. Operate instructions have the format opcode{#} reg,reg{,skip} In all Nova instructions, blanks may be substituted for commas as field delimiters. 7. PDP-1 Features The PDP-1 is configured as follows: device simulates name(s) CPU PDP-1 CPU with up to 64KW of memory PTR,PTP integral paper tape reader/punch TTI,TTO Flexowriter typewriter input/output LPT Type 62 line printer The PDP-1 simulator implements the following unique stop conditions: - an unimplemented instruction is decoded, and register STOP_INST is set - more than INDMAX indirect addresses are detected during memory reference address decoding - more than XCTMAX nested executes are detected during instruction execution - wait state entered, and no I/O operations outstanding (ie, no interrupt can ever occur) 7.1 CPU The only CPU options are the presence of hardware multiply/divide and the size of main memory. SET CPU MDV enable multiply/divide SET CPU NOMDV disable multiply/divide SET CPU 4K set memory size = 4K SET CPU 8K set memory size = 8K SET CPU 12K set memory size = 12K SET CPU 16K set memory size = 16K SET CPU 20K set memory size = 20K SET CPU 24K set memory size = 24K SET CPU 28K set memory size = 28K SET CPU 32K set memory size = 32K SET CPU 48K set memory size = 48K SET CPU 64K set memory size = 64K If memory size is being reduced, and the memory being truncated contains non-zero data, the simulator asks for confirmation. Data in the truncated portion of memory is lost. Initial memory size is 64K. CPU registers include the visible state of the processor as well as the control registers for the interrupt system. name size comments PC 16 program counter AC 18 accumulator IO 18 IO register OV 1 overflow flag PF 6 program flags<1:6> SS 6 sense switches<1:6> TW 18 test word (front panel switches) EXTM 1 extend mode IOSTA 18 IO status register SBON 1 sequence break enable SBRQ 1 sequence break request SBIP 1 sequence break in progress IOH 1 I/O halt in progress IOC 1 I/O continue OLDPC 16 PC prior to last transfer STOP_INST 1 stop on undefined instruction SBS_INIT 1 initial state of sequence break enable EXTM_INIT 1 initial state of extend mode BREAK 17 breakpoint address (377777 to disable) WRU 8 interrupt character 7.2 Programmed I/O Devices (PTR, PTP, TTI, TTO, LPT) The paper tape reader (PTR), paper tape punch (PTP), and line printer (LPT) read data from or write data to disk files. The POS register specifies the number of the next data item to be read or written. Thus, by changing POS, the user can backspace or advance these devices. The programmed I/O devices typically implement these registers: name size comments BUF 8 last data item processed DONE 1 device done flag RPLS 1 return restart pulse flag TIME 24 time from I/O initiation to interrupt (for keyboard, polling interval) POS 31 position in the input or output file STOP_IOE 1 stop on I/O error For the serial devices, error handling is as follows: type error STOP_IOE processed as in,out not attached 1 report error and stop 0 out of tape or paper in end of file 1 report error and stop 0 out of tape or paper in,out OS I/O error x report error and stop 7.3 Symbolic Display and Input The PDP-1 simulator implements symbolic display and input. Display is controlled by command line switches: -a display as ASCII character -c display as FIODEC character string -m display instruction mnemonics Input parsing is controlled by the first character typed in or by command line switches: ' or -a ASCII character " or -c three character FIODEC string alphabetic instruction mnemonic numeric octal number Instruction input uses modified PDP-1 assembler syntax. There are six instruction classes: memory reference, shift, skip, operate, IOT, and LAW. Memory reference instructions have the format memref {I} address where I signifies indirect reference. The address is an octal number in the range 0 - 0177777. Shift instructions have the format shift shift_count The shift count is an octal number in the range 0-9. Skip instructions consist of single mnemonics, eg, SZA, SZS4. Skip instructions may be or'd together skip skip skip... The sense of a skip can be inverted by including the mnemonic I. Operate instructions consist of single mnemonics, eg, CLA, CLI. Operate instructions may be or'd together opr opr opr... IOT instructions consist of single mnemonics, eg, TYI, TYO. IOT instructions may include an octal numeric modifier or the modifier I: iot modifier The simulator does not check the legality of skip, operate, or IOT combinations. Finally, the LAW instruction has the format LAW {I} immediate where immediate is in the range 0 to 07777. 7.4 Character Sets The PDP-1's console was a Frieden Flexowriter; its character encoding was known as FIODEC. The PDP-1's line printer used a modified Hollerith character set. The following table provides equivalences between ASCII characters and the PDP-1's I/O devices. In the console table, UC stands for upper case. PDP-1 PDP-1 ASCII console line printer 000 - 007 none none bs 075 none tab 036 none 012 - 014 none none cr 077 none 016 - 037 none none space 000 000 ! {OR} UC+005 none " UC+001 none # {IMPLIES} UC+004 none $ none none % none none & {AND} UC+006 none ' UC+002 none ( 057 057 ) 055 055 * {TIMES} UC+073 072 + UC+054 074 , 033 033 - 054 054 . 073 073 / 021 021 0 020 020 1 001 001 2 002 002 3 003 003 4 004 004 5 005 005 6 006 006 7 007 007 8 010 010 9 011 011 : none none ; none none < UC+007 034 = UC+033 053 > UC+010 034 ? UC+021 037 @ {MID DOT} 040 {MID DOT} 040 A UC+061 061 B UC+062 062 C UC+063 063 D UC+064 064 E UC+065 065 F UC+066 066 G UC+067 067 H UC+070 070 I UC+071 071 J UC+041 041 K UC+042 042 L UC+043 043 M UC+044 044 N UC+045 045 O UC+046 046 P UC+047 047 Q UC+050 050 R UC+051 051 S UC+022 022 T UC+023 023 U UC+024 024 V UC+025 025 W UC+026 026 X UC+027 027 Y UC+030 030 Z UC+031 031 [ UC+057 none \ {OVERLINE} 056 {OVERLINE} 056 ] UC+055 none ^ {UP ARROW} UC+011 {UP ARROW} 035 _ UC+040 UC+040 ` {RT ARROW} UC+020 036 a 061 none b 062 none c 063 none d 064 none e 065 none f 066 none g 067 none h 070 none i 071 none j 041 none k 042 none l 043 none m 044 none n 045 none o 046 none p 047 none q 050 none r 051 none s 022 none t 023 none u 024 none v 025 none w 026 none x 027 none y 030 none z 031 none { none none | UC+056 076 } none none ~ UC+003 013 del 075 none 8. 18b PDP Features The other four 18b PDP's (PDP-4, PDP-7, PDP-9, PDP-15) are very similar and are configured as follows: system device simulates name(s) PDP-4 CPU PDP-4 CPU with 8KW of memory PTR,PTP integral paper tape/Type 75 punch TTI,TTO KSR28 console terminal (Baudot code) LPT Type 62 line printer (Hollerith code) CLK integral real-time clock PDP-7 CPU PDP-7 CPU with 32KW of memory - Type 177 extended arithmetic element (EAE) - Type 148 memory extension PTR,PTP Type 444 paper tape reader/Type 75 punch TTI,TTO KSR 33 console terminal LPT Type 647 line printer CLK integral real-time clock DRM Type 24 serial drum PDP-9 CPU PDP-9 CPU with 32KW of memory - KE09A extended arithmetic element (EAE) - KG09B memory extension - KP09A power detection - KX09A memory protection PTR,PTP PC09A paper tape reader/punch TTI,TTO KSR 33 console terminal LPT Type 647E line printer CLK integral real-time clock RF RF09/RS09 fixed-head disk MT TC59/TU10 magnetic tape PDP-15 CPU PDP-15 CPU with 32KW of memory - KE15 extended arithmetic element (EAE) - KF15 power detection - KM15 memory protection PTR,PTP PC15 paper tape reader/punch TTI,TTO KSR 35 console terminal LPT LP15 line printer CLK integral real-time clock RP RP15/RP02 disk pack RF RF15/RS09 fixed-head disk MT TC59/TU10 magnetic tape The 18b PDP simulators implement several unique stop conditions: - an unimplemented instruction is decoded, and register STOP_INST is set - more than XCTMAX nested executes are detected during instruction execution 8.1 CPU The only CPU options are the presence of the EAE and the size of main memory. SET CPU EAE enable EAE SET CPU NOEAE disable EAE SET CPU 4K set memory size = 4K SET CPU 8K set memory size = 8K SET CPU 12K set memory size = 12K SET CPU 16K set memory size = 16K SET CPU 20K set memory size = 20K SET CPU 24K set memory size = 24K SET CPU 28K set memory size = 28K SET CPU 32K set memory size = 32K SET CPU 48K set memory size = 48K SET CPU 64K set memory size = 64K SET CPU 80K set memory size = 80K SET CPU 96K set memory size = 96K SET CPU 112K set memory size = 112K SET CPU 128K set memory size = 128K Memory sizes greater than 8K are only available on the PDP-7, PDP-9, and PDP-15; memory sizes greater than 32KW are only available on the PDP-15. If memory size is being reduced, and the memory being truncated contains non-zero data, the simulator asks for confirmation. Data in the truncated portion of memory is lost. Initial memory size is 8K for the PDP-4, 32K for the PDP-7 and PDP-9, and 128K for the PDP-15. CPU registers include the visible state of the processor as well as the control registers for the interrupt system. system name size comments all PC addr program counter 7,9 PC 15 program counter 15 PC 17 program counter all AC 18 accumulator 7,9,15 MQ 18 multiplier-quotient 7,9,15 SC 6 shift counter 7,9,15 EAE_AC_SIGN 1 EAE AC sign all L 1 link 7,9 EXTM 1 extend mode 15 BANKM 1 bank mode 7 TRAPM 1 trap mode 9,15 USMD 1 user mode 9,15 USMDBUF 1 user mode buffer 9,15 BR addr memory protection bounds 7,9,15 TRAPP 1 trap pending 9,15 NEXM 1 non-existent memory violation 9,15 PRVN 1 privilege violation 7,9 EMIRP 1 EMIR instruction pending 9,15 RESTP 1 DBR or RES instruction pending 15 XR 18 index register 15 LR 18 limit register all SR 18 front panel switches all INT 32 interrupt requests all IORS 18 IORS register all ION 1 interrupt enable all ION_DELAY 2 interrupt enable delay all OLDPC addr PC prior to last transfer all STOP_INST 1 stop on undefined instruction all BREAK 18 breakpoint address (777777 to disable) all WRU 8 interrupt character "addr" signifies the address width of the system (13b for the PDP-4, 15b for the PDP-7 and PDP-9, 17b for the PDP-15). 8.2 Programmed I/O Devices (PTR, PTP, TTI, TTO, CLK, LPT) The paper tape reader (PTR), paper tape punch (PTP), and line printer (LPT) read data from or write data to disk files. The POS register specifies the number of the next data item to be read or written. Thus, by changing POS, the user can backspace or advance these devices. The teletype reads and writes to the controlling console port. The keyboard has one option, UC; when set, it automatically converts lower case input to upper case. The programmed I/O devices typically implement these registers: name size comments BUF 8 last data item processed INT 1 interrupt pending flag DONE 1 device done flag TIME 24 time from I/O initiation to interrupt (for keyboard, polling interval) POS 31 position in the input or output file STOP_IOE 1 stop on I/O error For the serial devices, error handling is as follows: type error STOP_IOE processed as in,out not attached 1 report error and stop 0 out of tape or paper in end of file 1 report error and stop 0 out of tape or paper in,out OS I/O error x report error and stop 8.3 RP15/RP02 RP15 options include the ability to make units write enabled or write locked: SET RPn LOCKED set unit n write locked SET RPn ENABLED set unit n write enabled Units can also be REMOVEd or ADDed to the configuration. The RP15 implements these registers: name size comments STA 18 status A STB 18 status B DA 18 disk address MA 18 current memory address WC 18 word count INT 1 interrupt pending flag BUSY 1 control busy flag STIME 24 seek time, per cylinder RTIME 24 rotational delay STOP_IOE 1 stop on I/O error Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready end of file x assume rest of disk is zero OS I/O error x report error and stop 8.4 DRM The drum has no options. It implements these registers: name size comments DA 9 drum address (sector number) MA 15 current memory address INT 1 interrupt pending flag DONE 1 device done flag ERR 1 error flag WLK 32 write lock switches TIME 24 rotational latency, per word STOP_IOE 1 stop on I/O error Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready Drum data files are buffered in memory; therefore, end of file and OS I/O errors cannot occur. 8.5 RF09/RF15/RS09 The RF09/RF15 implements these registers: name size comments STA 18 status DA 21 current disk address MA 18 memory address (in memory) WC 18 word count (in memory) BUF 18 data buffer (diagnostic only) INT 1 interrupt pending flag WLK0..7 16 write lock switches for disks 0..7 TIME 24 rotational delay, per word BURST 1 burst flag STOP_IOE 1 stop on I/O error The RF09/RF15 is a three-cycle data break device. If BURST = 0, word transfers are scheduled individually; if BURST = 1, the entire transfer occurs in a single data break. Error handling is as follows: error STOP_IOE processed as not attached 1 report error and stop 0 disk not ready RF15/RF09 data files are buffered in memory; therefore, end of file and OS I/O errors cannot occur. 8.6 Magnetic Tape (MT) Magnetic tape options include the ability to make units write enabled or or write locked. SET MTn LOCKED set unit n write locked SET MTn ENABLED set unit n write enabled Units can also be REMOVEd or ADDed to the configuration. The magnetic tape controller implements these registers: name size comments CMD 18 command STA 18 main status MA 18 memory address (in memory) WC 18 word count (in memory) INT 1 interrupt pending flag STOP_IOE 1 stop on I/O error TIME 24 record delay UST0..7 24 unit status, units 0..n POS0..7 31 position, units 0..n Error handling is as follows: error processed as not attached tape not ready end of file (read or space) end of physical tape (write) ignored OS I/O error report error and stop 8.7 Symbolic Display and Input The 18b PDP simulators implement symbolic display and input. Display is controlled by command line switches: -a display as ASCII character -c display as (sixbit) character string -m display instruction mnemonics The PDP-15 also recognizes an additional switch: -p display as packed ASCII (five 7b ASCII characters in two 18b words) Input parsing is controlled by the first character typed in or by command line switches: ' or -a ASCII character " or -c three character sixbit string alphabetic instruction mnemonic numeric octal number The PDP-15 also recognizes an additional input mode: # or -p five character packed ASCII string in two 18b words Instruction input uses standard 18b PDP assembler syntax. There are six instruction classes: memory reference, EAE, index (PDP-15 only), IOT, operate, and LAW. Memory reference instructions have the format memref {I/@} address{,X} where I (PDP-4, PDP-7, PDP-9) /@ (PDP-15) signifies indirect reference, and X signifies indexing (PDP-15 in page mode only). The address is an octal number in the range 0 - 017777 (PDP-4, PDP-7, PDP-9, and PDP-15 in bank mode) or 0 - 07777 (PDP-15 in page mode). IOT instructions consist of single mnemonics, eg, KRB, TLS. IOT instructions may be or'd together iot iot iot... IOT's may also include the number 10, signifying clear the accumulator iot 10 The simulator does not check the legality of IOT combinations. IOT's for which there is no opcode may be specified as IOT n, where n is an octal number in the range 0 - 07777. EAE instructions have the format eae {+/- shift count} EAE instructions may be or'd together eae eae eae... The simulator does not check the legality of EAE combinations. EAE's for which there is no opcode may be specified as EAE n, where n is an octal number in the range 0 - 037777. Index instructions (PDP-15 only) have the format index {immediate} The immediate, if allowed, must be in the range of -0400 to +0377. Operate instructions have the format opr opr opr... The simulator does not check the legality of the proposed combination. The operands for MUY and DVI must be deposited explicitly. Finally, the LAW instruction has the format LAW immediate where immediate is in the range of 0 to 017777. 8.8 Character Sets The PDP-4's console was an ASR-28 Teletype; its character encoding was Baudot. The PDP-4's line printer used a modified Hollerith character set. The PDP-7's and PDP-9's consoles were KSR-33 Teletypes; their character sets were basically ASCII. The PDP-7's and PDP-9's line printers used sixbit encoding (ASCII codes 040 - 0137 masked to six bits). The PDP-15's I/O devices were all ASCII. The following table provides equivalences between ASCII characters and the PDP-4's I/O devices. In the console table, FG stands for figures (upper case). PDP-4 PDP-4 ASCII console line printer 000 - 006 none none bell FG+024 none 010 - 011 none none lf 010 none 013 - 014 none none cr 002 none 016 - 037 none none space 004 000 ! FG+026 none " FG+021 none # FG+005 none $ FG+062 none % none none & FG+013 none ' FG+032 none ( FG+036 057 ) FG+011 055 * none 072 + none 074 , FG+006 033 - FG+030 054 . FG+007 073 / FG+027 021 0 FG+015 020 1 FG+035 001 2 FG+031 002 3 FG+020 003 4 FG+012 004 5 FG+001 005 6 FG+025 006 7 FG+034 007 8 FG+014 010 9 FG+003 011 : FG+016 none ; FG+017 none < none 034 = none 053 > none 034 ? FG+023 037 @ none {MID DOT} 040 A 030 061 B 023 062 C 016 063 D 022 064 E 020 065 F 026 066 G 013 067 H 005 070 I 014 071 J 032 041 K 036 042 L 011 043 M 007 044 N 006 045 O 003 046 P 015 047 Q 035 050 R 012 051 S 024 022 T 001 023 U 034 024 V 017 025 W 031 026 X 027 027 Y 025 030 Z 021 031 [ none none \ none {OVERLINE} 056 ] none none ^ none {UP ARROW} 035 _ none UC+040 0140 - 0177 none none 9. IBM 1401 Features The IBM 1401 simulator is configured as follows: device simulates name(s) CPU IBM 1401 CPU with 16K of memory CDR,CDP IBM 1402 card reader/punch LPT IBM 1403 line printer INQ IBM 1407 inquiry terminal MT IBM 729 7-track magnetic tape controller with six drives The IBM 1401 simulator implements many unique stop conditions. On almost any kind of error the simulator stops: unimplemented opcode reference to non-existent memory reference to non-existent device no word mark under opcode invalid A address invalid B address invalid instruction length invalid modifier character invalid branch address invalid magtape unit number invalid magtape record length write to locked magtape drive skip to unpunched carriage control tape channel card reader hopper empty address register wrap-around single character A field in MCE single character B field in MCE hanging $ in MCE with EPE enabled I/O check with I/O stop switch set 9.1 CPU The CPU options include a number of special features and the size of main memory. Note that the Modify Address special feature is always included when memory size is greater than 4K. SET CPU XSA enable advanced programming special feature SET CPU NOXSA disable advanced programming SET CPU HLE enable high/low/equal special feature SET CPU NOHLE disable high/low/equal SET CPU BBE enable branch on bit equal special feature SET CPU NOBBE disable branch on bit equal SET CPU MR enable move record special feature SET CPU NOMR disable move record SET CPU EPE enable extended print edit special feature SET CPU NOEPE disable extended print edit SET CPU 4K set memory size = 4K SET CPU 8K set memory size = 8K SET CPU 12K set memory size = 12K SET CPU 16K set memory size = 16K If memory size is being reduced, and the memory being truncated contains non-zero data, the simulator asks for confirmation. Data in the truncated portion of memory is lost. Initially, memory size is 16K, and all special features are enabled. Memory is implemented as 7 bit BCD characters, as follows: 6 5 4 3 2 1 0 word B bit A bit 8 4 2 1 mark <-- zone --> <-------- digit --------> In BCD, the decimal digits 0-9 are (octal) values 012, 001, 002, 003, 004, 005, 006, 007, 010, 011, respectively. Signs are encoded in the zone bits, with 00, 01, and 11 being positive, and 10 being negative. CPU registers include the visible state of the processor. The 1401 has no interrupt system. name size comments IS 14 instruction storage address register (PC) AS 14 A storage address register BS 14 B storage address register ASERR 1 AS invalid flag BSERR 1 BS invalid flag SSA 1 sense switch A SSB 1 sense switch B SSC 1 sense switch C SSD 1 sense switch D SSE 1 sense switch E SSF 1 sense switch F SSG 1 sense switch G EQU 1 equal compare indicator UNEQ 1 unequal compare indicator HIGH 1 high compare indicator LOW 1 low compare indicator OVF 1 overflow indicator IOCHK 1 I/O check switch PRCHK 1 process check switch OLDIS 1 IS prior to last branch BREAK 17 breakpoint address (1000000 to disable) WRU 8 interrupt character 9.2 Card Reader/Punch The IBM 1402 card/reader punch is simulated as three independent devices: the card reader (CDR), the card punch (CDP), and the reader and punch stackers (STKR). STRK units 0, 1, 2, and 4 correspond to the reader normal stacker, reader stacker 1, shared stacker 2/8, and punch stacker 4, respectively. The card reader reads data from disk files, while the punch and stackers write data to disk files. Cards are simulated as ASCII text lines with terminating newlines; column binary is not supported. For each unit, the POS register specifies the number of the next data item to be read or written. Thus, by changing POS, the user can backspace or advance these devices. The reader/punch registers are: device name size comments CDR LAST 1 last card indicator ERR 1 error indicator S1 1 stacker 1 select flag S2 1 stacker 2 select flag POS 31 position TIME 24 delay window for stacker select CDP ERR 1 error indicator S4 1 stacker 4 select flag S8 1 stacker 8 select flag STKR POS0 31 position, normal reader stack POS1 31 position, reader stacker 1 POS2 31 position, shared stacker 2/8 POS4 31 position, punch stacker 4 Error handling is as follows: device error processed as reader end of file if SSA set, set LAST indicator on next Read, report error and stop reader,punch not attached report error and stop OS I/O error print error message if IOCHK set, report error and stop otherwise, set ERR indicator stacker not attached ignored OS I/O error print error message if IOCHK set, report error and stop 9.3 Line Printer The IBM 1403 line printer (LPT) writes its data, converted to ASCII, to a disk file. The line printer supports three different print character sets or "chains": SET LPT PCF full 64 character chain SET LPT PCA 48 character business chain SET LPT PCH 48 character FORTRAN chain In addition, the line printer can be programmed with a carriage control tape. The LOAD command loads a new carriage control tape: LOAD load carriage control tape file The format of a carriage control tape consists of multiple lines. Each line contains an optional repeat count, enclosed in parentheses, optionally followed by a series of column numbers separated by commas. Column numbers must be between 1 and 12; a column number of zero denotes top of form. The following are all legal carriage control specifications: no punch (5) 5 lines with no punches 1,5,7,8 columns 1, 5, 7, 8 punched (10)2 10 lines with column 2 punched 1,0 column 1 punched; top of form The default form is 66 lines long, with column 1 and the top of form mark on line 1, and the rest blank. The line printer registers are: name size comments LINES 8 number of newlines after next print LFLAG 1 carriage control flag (1 = skip, 0 = space) CCTP 8 carriage control tape pointer CCTL 8 carriage control tape length (read only) ERR 1 error indicator POS 31 position Error handling is as follows: error processed as not attached report error and stop OS I/O error print error message if IOCHK set, report error and stop otherwise, set ERR indicator 9.4 Inquiry Terminal The IBM 1407 inquiry terminal (INQ) is a half-duplex console. It polls the controlling keyboard of the simulator periodically for inquiry requests. The inquiry terminal registers are: name size comments INQC 7 inquiry request character (initially ESC) INR 1 inquiry request indicator INC 1 inquiry cleared indicator TIME 24 polling interval When the 1401 CPU requests input from the keyboard, the message [Enter] is printed out, followed by a new line. The CPU hangs waiting for input until either the return/enter key is pressed, or the inquiry request character is typed in. The latter cancels the type-in and sets INC. The inquiry terminal has no errors. 9.5 Magnetic Tape (MT) The magnetic tape controller supports six drives, numbered 1 through 6. Magnetic tape options include the ability to make units write enabled or or write locked. SET MTn LOCKED set unit n write locked SET MTn ENABLED set unit n write enabled Units can also be REMOVEd or ADDed to the configuration. The magnetic tape controller implements these registers: name size comments END 1 end of file indicator ERR 1 error indicator PAR 1 parity error indicator POS1..6 31 position, drives 1..6 Error handling is as follows: error processed as not attached report error and stop end of file (read or space) end of physical tape (write) ignored OS I/O error print error message if IOCHK set, report error and stop otherwise, set ERR indicator 9.6 Symbolic Display and Input The IBM 1401 simulator implements symbolic display and input. Display is controlled by command line switches: -c display as single character (BCD for CPU and MT, ASCII for others) -s display as wordmark terminated BCD string (CPU only) -m display instruction mnemonics (CPU only) In a CPU character display, word marks are denoted by ~. Input parsing is controlled by the first character typed in or by command line switches: ' or " or -c or -s characters (BCD for CPU and MT, ASCII for others) alphabetic instruction mnemonic numeric octal number Instruction input is free format, with spaces separating fields. There are six instruction formats: 1, 2, 4, 5, 7, and 8 characters: 1 character opcode 2 character opcode 'modifier 4 character opcode address 5 character opcode address 'modifier 7 character opcode address address 8 character opcode address address 'modifier Addresses are always decimal, except for special I/O addresses in the A field, which may be specified as %xy, where x denotes the device and y the unit number. For the CPU, string input may encompass multiple characters. A word mark is denoted by ~ and must precede the character to be marked. All other devices can only accept single character input, without word marks. 9.7 Character Sets The IBM 1401 used a 6b character code called BCD (binary coded decimal). Some of the characters have no equivalent in ASCII and require different representations: BCD ASCII IBM 1401 print code representation character chains 00 space 01 1 02 2 03 3 04 4 05 5 06 6 07 7 10 8 11 9 12 0 13 # = in H chain 14 @ ' in H chain 15 : blank in A, H chains 16 > blank in A, H chains 17 ( tape mark blank in A, H chains 20 ^ alternate blank blank in A, H chains 21 / 22 S 23 T 24 U 25 V 26 W 27 X 30 Y 31 Z 32 ' record mark 33 , 34 % ( in H chain 35 = word mark blank in A, H chains 36 \ blank in A, H chains 37 + blank in A, H chains 40 - 41 J 42 K 43 L 44 M 45 N 46 O 47 P 50 Q 51 R 52 ! 53 $ 54 * 55 ] blank in A, H chains 56 ; blank in A, H chains 57 _ delta blank in A, H chains 60 & 61 A 62 B 63 C 64 D 65 E 66 F 67 G 70 H 71 I 72 ? 73 . 74 ) lozenge 75 [ blank in A, H chains 76 < blank in A, H chains 77 " group mark blank in A, H chains Appendix 1: File Representations All file representations are little endian. On big endian hosts, the simulator automatically performs any required byte swapping. 1. Hard Disks Hard disks are represented as unstructured binary files of 16b data items for the 12b and 16b simulators, and of 32b data items for the 18b simulators. 2. Floppy Disks PDP-8 and PDP-11 floppy disks are represented as unstructured binary files of 8b data items. They are nearly identical to the floppy disk images for Doug Jones' PDP-8 simulator but lack the initial 256 byte header. A utility for converting between the two formats is easily written. 3. Magnetic Tapes Magnetic tapes are represented as unstructured binary files of 8b data items. Each record consists of a 32b byte count n, in little endian format, followed by n 8b bytes of data, followed by a repeat of the 32b byte count. If the byte count is odd, the record is padded to even length; the pad byte is undefined. Magnetic tapes are endian independent and consistent across simulator families. A magtape produced by the Nova simulator will appear to have its 16b words byte swapped if read by the PDP-11 simulator. 4. Line Printers Line printer output is represented by an ASCII file of lines separated by the newline character. Overprinting is represented by a line ending in return rather than newline. Appendix 2: Sample Software 1. PDP-8 1.1 ESI-X ESI-X is an interactive program for technical computation. It can execute both immediate commands and stored programs (like BASIC). ESI-X is provided as both source and as a binary loader format paper-tape image. For more information see the documentation included with the program. My thanks to Dave Waks, who wrote the program, and to Paul Pierce and Tim Litt, who recovered the source from its archival medium. To load and run ESI-X: sim> load esix.bin sim> run 5400 _TYPE 2+2. 2+2 = 4 1.2 FOCAL69 FOCAL69 is an interactive program for technical computations. It can execute both immediate commands and stored programs (like BASIC). FOCAL69 is provided as a binary loader format paper-tape image. To load and run FOCAL69: sim> load focal69.bin sim> run 200 *TYPE 2+2 = 4.000* 1.3 PDP-8 OS/8 OS/8 is the PDP-8's mass storage-based operating system. It provides a program development and execution environment for assembler, BASIC, and FORTRAN programs. OS/8 is provided under license, as is, without fee, by Digital Equipment Corporation, for non-commercial use only. Please read the enclosed license agreement for full terms and conditions. This license agreement must be reproduced with any copy of the OS/8 disk images. My thanks to Doug Jones of the University of Iowa, who provided the disk images, and to Digital Equipment Corporation, which provided the license. To boot and run OS/8: sim> att rx0 os8sys_rx.dsk sim> att rx1 os8f4_rx.dsk sim> boot rx0 .DA dd-mmm-yy . Note that OS/8 only recognizes upper case characters. The first disk (drive 0) is the system disk; it also includes BASIC. The second disk (drive 1) includes FORTRAN. 2. PDP-11 2.1 UNIX V5, V6, V7 UNIX was first developed on the PDP-7; its first widespread usage was on the PDP-11. UNIX provides a program development and execution environment for assembler and C programs. UNIX V5, V7, V7 for the PDP-11 is provided under license, as is, without fee, by Santa Cruz Organization (SCO), for non-commercial use only. Please read the enclosed license agreement for full terms and conditions. This license must be reproduced with any copy of the UNIX V5, V6, V7 disk images. My thanks to PUPS, the PDP-11 UNIX Preservation Society of Australia, which provided the disk images, and to SCO, which provided the license. 2.1.1 UNIX V5 UNIX V5 is contained on a single RK05 disk image. To boot UNIX: sim> set cpu 18b sim> att rk0 unix_v5_rk.dsk sim> boot rk @unix login: root #ls -l 2.1.2 UNIX V6 UNIX V6 is contained on three RK05 disk images. To boot UNIX: sim> set cpu 18b sim> att rk0 unix0_v6_rk.dsk sim> att rk1 unix1_v6_rk.dsk sim> att rk3 unix3_v6_rk.dsk sim> boot rk0 @unix login: root # ls -l 2.1.3 UNIX V7 UNIX V7 is contained on a single RL02 disk image. To boot UNIX: sim> set cpu 18b sim> set rl0 RL02 sim> att rl0 unix_v7_rl.dsk sim> boot rl0 @unix login: root password: pdp # ls -l A smaller image is contained on a single RK05 disk image. To boot UNIX: sim> set cpu 18b sim> att rk0 unix_v7_rk.dsk sim> boot rk0 @rkunix login: root password: pdp # ls -l 2.2 RT-11 RT-11 is the PDP-11's single user operating system. It provides a program development and execution environment for assembler, BASIC, and FORTRAN programs. RT-11 is provided under license, as is, without fee, by Mentec Corporation, for non-commercial use ONLY ON THIS SIMULATOR. Please read the enclosed license agreement for full terms and conditions. This license agreement must be reproduced with any copy of the RT-11 disk image. My thanks to John Wilson, a private collector, who provided the disk image, and to Mentec Corporation, which provided the license. To boot and run RT-11: sim> att rk0 rtv4_rk.dsk sim> boot rk0 For RL01 and RL02 disks, RT-11 expects to find a manufacturer's bad block table in the last 20 sectors of the disk. Therefore, INITialization of a new (all zero's) disk fails, because there is no valid bad block table. To create a minimal bad block table, use the following commands: sim> att rl0 newdisk.dsk RL: creating new file sim> id rl0 11766000-11766004 for an RL01, or sim> id rl0 23766000-23766004 for an RL02 addr: 12345 first part of pack id addr+1: 67 second part of pack id addr+2: 0 null table addr+3: 0 addr+4: 177777 end of table 3. Nova RDOS RDOS is the Nova's real-time mass storage operating system. It provides a program development and execution environment for assembler, BASIC, and FORTRAN programs. RDOS is provided under license, as is, without fee, by Data General Corporation, for non-commercial use only. Please read the enclosed license agreement for full terms and conditions. This license agreement must be reproduced with any copy of the RDOS disk image. My thanks to Carl Friend, a private collector, who provided the disk image, and to Data General Corporation, which provided the license. To boot and run RDOS: sim> att dp0 rdos_d31.dsk sim> set tti dasher sim> boot dp0 FILENAME? (cr) DATE (mm/dd/yy)? xx/yy/zz TIME (hh:mm:ss)? hh:mm:ss R list/e 4. PDP-1 LISP PDP-1 LISP is an interactive interpreter for the Lisp language. It can execute both interactive commands and stored programs. The startup instructions for LISP are complicated; see the documentation included with the program for details. My thanks to Peter Deutsch, who wrote the program, to Gordon Greene, who typed it in from a printed listing, and to Paul McJones, who helped with the final debug process. 5. PDP-7 SIM8 PDP-7 SIM8 is a PDP-8 simulator for the PDP-7. It implements an 8K PDP-8/I with keyboard, teleprinter, reader, punch, and line printer. It provides an interactive console environment for control and debug of the simulated PDP-8. For more information see the documentation included with the program. My thanks to Dave Waks, who wrote the program, and to Paul Pierce and Tim Litt, who recovered the source from its archival medium. To load and run SIM8: sim> load sim8.rim sim> run AC/ 0000 6. 1401 Single Card "Koans" One of the art forms for the IBM 1401 was packing useful programs into a single punched card. Three samples are included: i1401_ctolp.cd prints a card deck on the line printer i1401_ctopu.cd copies a card deck to the card punch i1401_hello.cd prints "HELLO WORLD" on the line printer and stops To use the reproduction cards, simply insert them at the beginning of a text file, terminated by newline. Attach the modified file to the card reader, attach a blank file to the output device, and boot the card reader. Appendix 3: Debug Status The debug status of each simulated CPU and device is as follows: system PDP-8 PDP-11 Nova PDP-1 18b PDP's IBM 1401 device CPU y y y y y h FPU - h - - - - console y y y y y h paper tape y y y h y - card reader - - - - - h line printer y y y h y h clock y y y - h - hard disk y y y - h - fixed disk h - h - h - floppy disk y y y - - - mag tape h y y - h h legend: y = runs operating system or sample program d = runs diagnostics h = runs hand-generated test cases n = untested - = not applicable Revision History (since Rev 1.1) Rev 2.3a, Sep, 97 Added bootstrap to PDP-11 magtape Added RT-11 sample software Rev 2.3, Mar, 97 Changed UNIX terminal I/O to TERMIOS Changed magtape format to double ended Changed PDP-8 current page mnemonic from T to C Added endian independent I/O routines Added precise integer data types Fixed bug in sim_poll_kbd Fixed bug in PDP-8 binary loader Fixed bugs in TM11 magtape Fixed bug in RX11 bootstrap Fixed bug in 18b PDP ADD Fixed bug in 18b PDP paper tape reader Fixed bug in PDP-4 console Fixed bug in PDP-4,7 line printer Added PDP-11 RP Added PDP-1 Rev 2.2d, Dec, 96 Added ADD/REMOVE commands Added unit enable/disable support to device simulators Added features for IBM 1401 project Added switch recognition for symbolic input Fixed bug in variable length IEXAMINE Fixed LCD bug in RX8E Initial changes for Win32 Added IBM 1401 Rev 2.2b, Apr, 96 Added PDP-11 dynamic memory size support Rev 2.2a, Feb, 96 New endian independent magtape format Rev 2.2 Jan, 96 Added register buffers for save/restore Added 18b PDP's Guaranteed TTI, CLK times are non-zero Fixed breakpoint/RUN interaction bug Fixed magnetic tape backspace to EOF bug Fixed ISZ/DCA inversion in PDP-8 symbol table Fixed sixbit conversion in PDP-8 examine/deposit Fixed origin increment bug in PDP-11 binary loader Fixed GCC longjmp optimization bug in PDP-11 CPU Fixed unit number calculation bug in SCP and in Nova, PDP-11, 18b PDP moving head disks Rev 2.1 Dec, 95 Fixed PTR bug (setting done on EOF) in PDP-8, Nova Fixed RX bug (setting error on INIT if drive 1 is not attached) in PDP-8, PDP-11 Fixed RF treatment of photocell flag in PDP-8 Fixed autosize bug (always chose smallest disk if new file) in PDP-11, Nova Fixed not attached bug (reported as not attachable) in most mass storage devices Fixed Nova boot ROMs Fixed bug in RESTORE (didn't requeue if delay = 0) Fixed bug in RESTORE (clobbered device position) Declared static constant arrays as static const Added PDP-8, Nova magnetic tape simulators Added Dasher mode to Nova terminal simulator Added LINUX support Rev 2.0 May, 95 Added symbolic assembly/disassembly Acknowledgements Phil Budne Solaris debugging Max Burnet PDP information, documentation, and software James Carpenter LINUX debugging Peter Deutsch PDP-1 LISP software Carl Friend Nova documentation and RDOS software Megan Gentry PDP-11 integer debugging, make file Dick Greeley PDP-8 OS/8 and PDP-10 TOPS-10/20 legal permissions Gordon Greene PDP-1 LISP machine readable source Franc Grootjen PDP-11 2.11 BSD debugging Ken Harrenstein PDP-10 simulator Bill Haywood PDP-8 information, simulator, and software Jim Jaeger IBM 1401 information Doug Jones PDP-8 information, simulator, and software Don Lewine Nova documentation and legal permissions Scott McGregor PDP-11 UNIX legal permissions Paul Pierce IBM 1401 diagnostics, media recovery Craig St Clair PDP documentation Richard Schedler Public repository maintenance Stephen Schultz PDP-11 2.11 BSD debugging Brian Silverman PDP-1 simulator and software Hans-Michael Stahl OS/2 debugging, TERMIOS implementation Larry Stewart Initial suggestion for the project Chris Suddick PDP-11 floating point debugging Ben Thomas VMS character-by-character I/O routines Warren Toomey PDP-11 UNIX software Deb Toivonen PDP documentation Leendert Van Doorn PDP-11 UNIX V6 debugging, TERMIOS implementation David Waks PDP-8 ESI-X and PDP-7 SIM8 software John Wilson PDP-11 simulator and software Tom West Nova documentation