This page is dedicated to PDP-11 and compatible hardware and software as well as other vintage DEC systems such as the Rainbow 100. PDP-11-based computers are still manufactured today (e.g. by Mentec and Strobe) and emulated (e.g. by DBit); DEC no longer makes them and in any case has been absorbed by Compaq.
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New: Detailed instructions on converting PDP-11 disk images (E11 and Supnik emulator-compatible) to raw CD’s and vice versa. It might seem elementary, but some CD burners refuse to write such non–ISO-9660 “ISO” files or crash if it is attempted. In any case, it outlines a method useful for any kind of non-ISO file structure, to write it to CD and to recover tracks from a CD, converting them into disk images.
New: The Telnet Song, a recursive musical classic (Words and Music by The Great Quux; copyright © April 1984, Guy L. Steele, Jr. & D.E. Knuth; transcribed into MIDI and NWC formats by yours truly on 12/13-Aug-2001). Available in MIDI and NWC formats with N=2.
New: BCKRead and related utilities page has been updated; for copying from a VMS or AXP .BCK saveset to MSDOS or Files-11 disks, including blank disk image generator and blank disks, bootable and not.
New: P/OS I/O Driver Fiche, DEC #AH-CG61A-TK, contains source listings and maps for the P/OS Executive and drivers for DW:, DZ:, TT:, video fonts, etc. As it involves an enormous amount of scanning from paper copies of the fiches (each of the first 15 fiches contain up to 13x16 = 208 pages), it will take time to scan this in (and I'll probably skip the parts which seem to be the same as RSX-11M-Plus circa version 2, which is most of the Executive code, and considerably reduces the amount of scanning needed). I do hope to get the DZ and DW code and maybe parts of the TT code up soon, which is Pro-specific. Why DEC didn't supply it on floppies and make things easy is beyond me. Anyone else have the fiches and want to help out? So far I have made paper copies of ACSUB, INITL, DWDRV, DZDRV, NLDRV and the index on fiche 16 (to replace the thermal-paper copies made in the '80's which have long since faded). See how to allow DWDRV to recognize larger disks by zapping the NOP with a BR; P/OS V2.0 supports RD50-RD52 but support for other disks (e.g. RD53) can apparently be added very easily. May also be useful for anyone thinking of writing a Pro300 emulator.
NoFPP.CMD, a command file allowing use of Fortran-77 executables on a much wider variety of RSX systems. Allows M-only tasks to run on M-Plus, and allows F77 programs that don't use the FPP to run on a system without one. See the comments for details and usage instructions. Requires ZAP.TSK (not included, but available on any P/OS distribution with Toolkit [see below] or under RSX-11M, M-Plus, or RSX emulation under RSTS/E). This was used to make the QIOLOG for RSX disk editing utility and Pacman tasks run on all the systems I tried them on, with or without an FPP, on 11M, M-Plus, Micro RSX and P/OS, without relinking.
Calendar and Timeclock for P/OS and RSX, Pro/Basic and Basic-Plus-2 (originally under RT-11 Basic). The calendar program prints a full-size calendar on the line printer (or to a disk file in later versions) with a user-selectable ASCII-art image at the top; years can range from 1582 to 9999. Timeclock is a concatenation of TIME (an ASCII alarm clock) and CLOCK, an analog-display clock written by a classmate at college; the latter uses the Pro350's bitmap display and CORE Graphics Library calls. Calendar was on the PDP 11/23 (running RT-11 and TSX) at Northport High School, revised by E. Schaefer at a nearby school in March 1975; it was enhanced by David Kraus in November 1982. I ported it to the Pro 350 in September 1983 (when TIME and CLOCK were written) and to RSX in 2000. Updated for Y2K, supplied on RX50 floppy image with old and new versions and INKEY routine.
New for 2001: "2001: A Space Odyssey" -- this is the December 1978 Super Star Trek for RT11 on its own bootable disk image with documentation plus a Y2K-compatible 1998 sysgen of RT11SJ V5.01C and utilities such as CINIT and DIR2. Please note that this version of RT-11 is covered by Mentec's hobbyist license unless you have your own license with different terms. I include an E11.INI file for use with the E11 emulator, however it can also be used on a real PDP-11 or the Supnik or other emulators. Please keep in mind that only use on the Supnik emulator is covered by Mentec's hobbyist license included here. The E11.INI file can easily be used as a guide to the commands to use for the Supnik emulator; substitute ATTACH for MOUNT and boot the image (the key definitions and other frills are not needed unless you use KED/KEX or the single-line editor, which is disabled on this disk anyway). The SST software is provided on an RX02 image(zipped) and you can see my two highest scores in the High Score log, which also show that a file is missing (PLAQUE.SAV). If anyone has this file I'd be grateful to be able to complete the fileset.
A very rudimentary and incomplete emulation of the P/OS V2.0a Main Menu for MS/PC-DOS. It is a .COM file with .TASM source code for any 80x86 machine with DOS or Windoze.
DTIME V1.01 - a replacement for TIM that is Y2K and Y3K compliant! (This version supersedes all older versions, e.g. V1.00 / DTIME2.ZIP). Especially useful to set and display the time on the Pro 350 (it is Y2K OK but not Y3K on the Pro) but works on old and new RSX as well, with the same syntax as RSX TIM except one uses the DTI (or any other chosen abbreviation) command instead of TIM. Years are always displayed with four digits, but can be entered with 2 or 4 digits in both the 20th and 21st centuries (which TIM can't do). Supplied on a disk image along with other goodies such as GREP and Y2K DATE subroutines for Macro-11 and high-level languages, with source code.
RSX-11M/M-Plus page -- some new programs and updates for RSX-11M (see also Pro 350 area), and BRU Reader V1.1 for MS/PC-DOS. For reading VMS Backup files under MS/PC-DOS, as well as many other file transfer utilities for various systems, click here for the BCKREAD page. Patches for Fortran (IV and 77) to enable use on systems with no FPP and to add Year 2000 compliance also available, works on Pro 350 and all other tested platforms, for RT-11 and P/OS / RSX.
Emergency Boot Disk for Pro 325/350/380 with various utilities, useful for recovering data from hard disk when P/OS refuses to boot or is corrupted; can also fix certain file structure errors via the logical/physical block editor. Click here to download it, and click here to get the updated version 4.6 of QIOLOG.TSK (1999) for these utilities. The disks themselves were made in 1984. See the readme files at either location for more information on these utilities. Note that the new QIOLOG is much bigger than the old one since it was linked without using resident libraries. Either the old (V4.5) or new (V4.6) QIOLOG will perform disk editing functions just as well under most circumstances, but V4.6 has a number of enhancements and a bugfix.
Note: some miscellaneous utilities which were formerly hosted on Tripod.com have been removed due to their remote loading policy and can now be found in this miscellaneous DEC subdirectory.
F11READ.COM: Files-11 index file information for MS/PC-DOS, works on index files and RSX/POS container files. Shows LBN allocation and lists the bitmap. Year-2000 compliant.
RT-11 Utilities and Year 2000 Patches Page
Please read the Read Me file first, then download the utilities, patches and accompanying information from here. The Y2K patches are intended for RT-11 V5.01C but will work with slight modifications on other versions such as V5.3. Please note that these are not provided by DEC or Mentec and are not supported by them or any third parties, including me. The monitor itself is not provided, since it is copyrighted by Mentec; only the patches are supplied. Mentec does not permit use of the source code by those not licensed to use it (but see here for binaries licensed for noncommercial use provided they are only used with the PDP-11 simulator by Robert Supnik).
However, the other programs which I wrote (e.g. DIR2) or obtained via disassembly from public-domain programs (e.g. EDMSG) or downloaded (PI.TEC) are not subject to these restrictions and thus the full source and executable code can be freely provided here. Also, P/OS and Venix do not require these licenses, and PDP-11 Unix is licensed by SCO or others; the details are here.
Most of the files should be transfered in binary mode, but the readme files and some of the source code is in Unix format (linefeed for newline), so that it will be easiest to use text/ASCII mode for them.
There is also more information on RT-11, Year 2000 and Mentec below.
Also: A patch for DIR.SAV V5.1C for versatile use with logical disks. This version is not yet Year 2000 compatible; the patch consists of a SIPP file and the documentation. Other enhancements are also planned.
I have posted a test program called DIR2 which was written without any DEC or Mentec code but does not have all the features of DIR; however it is fully Year 2000 compatible and handles any RT-11 date up to 31-Dec-2099. At this time, it does provide a standard listing of a directory, in decimal or octal, optionally narrowing the list down by such attributes as whether the file is protected or not, today's date, and other options. I have updated the old RT11DIR program on this site for Year 2000 compatibility; it is a simple DIR2 that reads RT-11 diskettes under P/OS or RSX. If anyone is using older versions of either DIR2 or RT11DIR, they should upgrade them, because the old versions had some bugs. Make sure the handler for the device you wish to read is loaded before running DIR2. The current version for both of these is V2.1. It is also available on a bootable disk image. The caveat about making sure the device handler is loaded also applies to TCONV; they behave unpredictably if it is not loaded and may freeze.
Mentec is now shipping RT-11 V5.7, fully Year 2000 compliant.
Mentec permits free downloading and personal, non-commercial use of older versions of RSTS, RSX and RT-11, under a license that accompanies most distributions on the net, a copy of which is provided here. Mentec themselves do not allow downloading; the disk images must be downloaded from a third party and Mentec does not provide support for them; the license is merely a courtesy to hobby users, who have after all provided much over the years in enhancements to these systems. The images covered by the license are to be used only on an emulated PDP-11, not a real PDP-11. Currently, the versions covered are RSTS V9.6 and prior, RT-11 V5.3 and prior, and RSX-11M V4.3 and prior. However, all versions of P/OS and Venix are public domain and not subject to any such licenses. And if you have obtained a real PDP-11 from a third party, you should be able to transfer the existing license. The permitted versions covered by the hobbyist license may gradually increase with time and the release of new versions from Mentec. See below for more information on obtaining and installing such disk images.
Utilities Galore: The Sunsite PDP-11 archives, including most DECUS archives for all PDP-11 operating systems.
Download Pro 300 series specific files (ROM image, disk and screen editors, RT-11 to P/OS utilities)
Update in Sweden: Get P/OS V3.2 and Toolkit for free!
The Pro300 series (325/350/380) is a PDP-11 compatible microcomputer released by DEC in 1983 which was supported until the early 1990's and still has its loyal users today. Though it was superior in many ways to the contemporary IBM PC's, it ran a watered-down version of RSX-11M-Plus called P/OS and was marketed poorly. Many were (and are?) used as front-ends for VAXstation systems. I still use it occasionally to access the internet via a 19,200 bps connection to a Unix shell account, where I can use elm, pine, tin, lynx, etc. One can also use Fuzzball for native internet capability on the Pro.
A Pro can also run RT-11, a fast and efficient realtime operating system which is discussed below (I also provide fixes and information for solving problems in 21st Century dates designed for Version 5.01C but useful for any version prior to V5.7, which should have full Y2K support).
For those with P/OS, the "Pro/Tool Kit", or Native Toolkit offers a command-line interface on the Pro that is very close to RSX-11M-Plus DCL. P/OS and RSX-11M-Plus share the same basic system calls (such as QIO$ and EXIT$), though P/OS has some calls of its own, like WIMP$ ("What's In My Professional" -- who said DEC doesn't have a sense of humor?). The Tool Kit supports standard RSX-11M+ Fortran 77, Macro-11, Pascal, Cobol and Dibol. There is a C package available from DECUS, and the Fortran and Macro-11 packages are also included in the freely downloadable archives of Update in Sweden (P/OS and Toolkit included). RSX and P/OS store only the lower two digits of filenames so the existing Files-11 structure can be used in any century, provided individual software does not make assumptions that would cause a date of 2002 (e.g.) to be treated as 1902. RSX-11M-Plus V4.5 is apparently fully year-2000 compliant, except for some minor issues in bundled software such as the date routines in Fortran-77, fixed in March 1998 (as noted on Mentec's Year 2000 page). Utilities such as PIP and RMSDSP have been fixed already and will work till at least 2027; the V4.6 updates apparently will extend this to c. 2100.
Under P/OS 2.0a (the latest version being 3.2) the Setup routine will only permit dates from 1982 to 1999, but this is only an issue if the battery powering the CMOS non volatile RAM (clock) dies (it uses standard NiCd cells, easily replaceable); the system will request the new time on the next reboot. This can be bypassed, and one can set the time from Tool Kit with standard DCL commands. Any user startup routine can be named [ZZSYS]STARTUP.TSK to be run as soon as the ROM and bootblock have been read; one can check for a password and/or Y2K issues and then chain to the original STARTUP.TSK (P/OS V2.0 and above have built-in password and account software). Also, one can either write one's own utilities or use PAT or ZAP to fix the P/OS tasks; most RSX-11M/M-Plus utilities are interchangeable with their P/OS counterparts.
The Pros offered high-resolution bitmap graphics, multitasking with hardware memory protection and 22-bit addressing of up to 4 megabytes of memory, when PC's were still in real mode and hadn't even reached 640K; this used the same orthogonal PDP-11 instruction set that had already been in use through the 1970's on the PDP-11.
They are provided for the benefit of RT-11 users with older versions and for educational use. I have removed as much original monitor code as possible from the old patch files, only leaving enough in so that one can find the correct location in the source file to patch, especially if one has a different version which differs somewhat. Also some lines which I commented are left in; I consider this a "fair use" commentary on the code (DEC stripped most comments from the originally-provided source code). To my knowledge, it is legal for a licensed RT-11 user to download this code. The code in lowercase is my own, and that is legal for anyone. If anyone wants specific legal advice however, I would suggest talking to a lawyer or checking one's license.
All of the newer (final) patches will be in SLP or SIPP format so that there is no question of infringing on any of Compaq/DEC's or Mentec's rights.
Version Information: The patches are for Version 5.1C. The current version is V5.7, which has a number of enhancements over the older versions, including full Year 2000 support (i.e. for dates through Dec. 31, 2099).
In some cases it is possible to obtain a low-cost or free license for hobbyist use, such as the OpenVMS Hobbyist License; if you acquire a PDP-11 from a third party along with its software, the transfer may or may not involve technicalities, according to discussions in November 1997 on vmsnet.pdp-11. The same discussion noted that DEC seems to have been much more lenient than Mentec in its terms of license transfer when PDP-11's change hands, often doing so for free. If you wish to obtain a software upgrade from Mentec, you should have your CPU serial number and DEC number, if available.
Old versions of many DEC OS's can often be used for free, if the use is noncommercial, as noted above. Note that they are not freeware, and Mentec still fully owns this software; they are just making it easier for hobbyists, who have provided many of the enhancements for these systems.
Needless to say, the patches are provided as is, without warranty (insert standard disclaimers here, except that I hate disclaimers :-), of course. However, I have tested it and it works on my version of RT-11. If you have different results with your version I may be able to help, and would like to know how other systems fare with these patches. However, the DIR.51C patch noted above should not be used on versions other than V5.1C unless you want to patch the patch.
For those who would like to patch RT-11 themselves, look at the code beginning with:
6$: MOV $DATE-$RMON(R0),R2
Hint: change the BIT #140000,R2 to BIT #140037,R2 and then process the high bits accordingly. The two high bits of the date word add to the 5 low bits of the year to give a year range of 1972-2099. One also needs to change the ROLOVR global routine if one has enabled month rollover in a SYSGENned monitor. There are also various other places that need to be patched, wherever the monitor or a utility reads the date (via the .DATE call, which expands to MOV #5000,R0; EMT 374, or 12700 5000 104374 in octal) and fails to take into account the effect of the year incrementing beyond 1999, or clears the two high bits summarily. For a complete fix, also patch the date references in the utilities: PIP, DIR, MACRO, SP, etc.
The PDP-11 was no longer supported by DEC as of December 31, 1997, and DEC itself has since been assimilated by Compaq, which seems to have decided that it is in its best interest not to obliterate DEC's identity totally. Actually, even in February 1999, while Altavista has the Compaq name on it, DEC's home pages still are DEC. However, "DEQ" no longer manufactures hardware or produces the software for PDP-11's anyway; that is Mentec's job; they now own RSTS, RSX, RT-11, etc. Mentec continues to manufacture PDP-11's, and companies such as Strobe Data manufacture PDP-11 clones-on-a-card.
According to Mentec, there are still many PDP-11's in commercial use, which drives the market for PDP-11 hardware and software regardless of DEC's action. Several third parties, noted below, continue to manufacture PDP-11-compatible hardware and have no plans to stop anytime soon. There are also emulators for Unix, MS-DOS and the Alpha (check the Relcom site for emulators for these or any other platforms). The Mentec updates, generally done and released between 1995 and 1998, make all the supported PDP-11 operating systems work with all dates up to at least 2099.
P/OS and Fuzzball are public-domain operating systems and freely available on the net. While P/OS was designed only for use on the Professional 300 series personal computers (which are based on a microcoded PDP-11 CPU design), the RSX utilities included with P/OS such as PIP and ZAP are identical to their RSX counterparts of the same version.
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