TSS/8
Developer | Digital Equipment Corporation |
---|---|
Written in | ALGOL, BASIC, FOCAL, Fortran D, PAL-D |
OS family | DEC OS family |
Working state | Discontinued |
Source model | Closed source |
Initial release | 1968 |
Latest release | 8.24 / January 1975[1][2] |
Platforms | PDP-8 |
Kernel type | Time-sharing operating systems |
Default user interface | Command-line interface |
License | Proprietary |
TSS-8 is a discontinued time-sharing operating system co-written by Don Witcraft and John Everett at Digital Equipment Corporation in 1967. DEC also referred to it as Timeshared-8 and EduSystem 50.[3]: p.2-15
The operating system ran on the 12-bit PDP-8 computer and was released in 1968.
Authorship
TSS/8 was designed at Carnegie Mellon University with graduate student Adrian van de Goor, in reaction to the cost, performance, reliability, and complexity of IBM's TSS/360 (for their Model 67).[4]
Don Witcraft wrote the TSS-8 scheduler, command decoder and UUO (Unimplemented User Operations) handler. John Everett wrote the disk handler, file system, TTY (teletypewriter) handler and 680-I service routine for TSS-8. Roger Pyle and John Everett wrote the PDP-8 Disk Monitor System, and John Everett adapted PAL-III to make PAL-D for DMS. Bob Bowering, author of MACRO for the PDP-6 and PDP-10, wrote an expanded version, PAL-X, for TSS-8.[5]
Architecture
This timesharing system:
was based on a protection architecture proposed by Adrian Van Der Goor, a grad student of Gordon Bell's at Carnegie-Mellon. It requires a minimum of 12K words of memory and a swapping device; on a 24K word machine, it could give good support for 17 users.[6] Each user gets a virtual 4K PDP-8; many of the utilities users ran on these virtual machines were only slightly modified versions of utilities from the Disk Monitor System or paper-tape environments. Internally, TSS-8 consists of RMON, the resident monitor, DMON, the disk monitor (file system), and KMON, the keyboard monitor (command shell). BASIC was well supported, while restricted (4K) versions of FORTRAN D and Algol were available.[7]
Like IBM's CALL/OS, it implemented language variants:[3]: pp.2-16 thru 2-18
- FORTRAN-D could only access 2 data files at a time, and the entire program was MAIN: no subroutines.
- BASIC programs were limited to 350 lines, but "chaining" allowed "programs of virtually any length."
- PAL-D (Program Assembly Language/Disk) allowed the "full standard" but, like all TSS-8 programs, was restricted to 4K.
- ALGOL was implemented as a known standard subset, "IFIP Subset ALGOL 60."
It also supported DEC's FOCAL, which was "developed specifically for the PDP 8/E" and it provided "an algebraic language" and also a "desk calculator mode."
Historical notes
- TSS/8 sold more than 100 copies[8][3]
- Operating costs were about 1/20th of TSS/360. TSS/8 was also designed to be more cost-effective than the PDP-10 "for jobs with low computational requirements (like editing)." [9][10]
- The RSTS-11 operating system is a descendant of TSS-8.[11]
References
- ^ "Running TSS/8 on the DEC PiDP-8/i and SIMH - Raymii.org".
- ^ "Digitol Software News" (PDF).
- ^ a b c in PDP 8/e Small Computer Handbook. Digital Equipment Corporation. 1973.
- ^ p.180,COMPUTER ENGINEERING" (C)'78 by DEC/Digital Press. C.Gordon Bell, J.Craig Mudge, John N. McNamara, ISBN 0-932376-00-2
- ^ FAQs
- ^ https://raymii.org/s/articles/Running_TSS_8_on_the_DEC_PiDP-8_i_and_SIMH.html
- ^ FAQs
- ^ "More than 100 ... in use today.." {1973)
- ^ http://www.computer.org/csdl/trans/tc/1969/11/01671170-abs.html
- ^ http://research.microsoft.com/en-us/um/people/gbell/CGB%2520Files/Design%2520and%2520Behavior%2520of%2520TSS8%2520IEEE%25206906%2520c.pdf
- ^ p.181,COMPUTER ENGINEERING" (C)'78 by DEC/Digital Press. C.Gordon Bell, J.Craig Mudge, John N. McNamara, ISBN 0-932376-00-2