Software:TSS-8

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Short description: 1968 operating system for the PDP-8 computer
TSS-8
DeveloperDigital Equipment Corporation
Written inALGOL, BASIC, FOCAL, Fortran D, PAL-D
OS familyDEC OS family
Working stateDiscontinued
Source modelClosed source
Initial release1968; 56 years ago (1968)
|Final release|Latest release}}8.24 / January 1975; 49 years ago (1975-01)[1][2]
PlatformsPDP-8
Kernel typeTime-sharing operating systems
Default user interfaceCommand-line interface
LicenseProprietary

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

  1. ↑ "Running TSS/8 on the DEC PiDP-8/i and SIMH - Raymii.org". https://raymii.org/s/articles/Running_TSS_8_on_the_DEC_PiDP-8_i_and_SIMH.html. 
  2. ↑ "Digitol Software News". http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/pdp8/softwarenews/197603_PDP8swNews_DEC-08-XSMAD-A-D.pdf. 
  3. ↑ 3.0 3.1 3.2 in PDP 8/e Small Computer Handbook. Digital Equipment Corporation. 1973. 
  4. ↑ p.180,COMPUTER ENGINEERING" (C)'78 by DEC/Digital Press. C.Gordon Bell, J.Craig Mudge, John N. McNamara, ISBN:0-932376-00-2
  5. ↑ FAQs
  6. ↑ https://raymii.org/s/articles/Running_TSS_8_on_the_DEC_PiDP-8_i_and_SIMH.html
  7. ↑ FAQs
  8. ↑ "More than 100 ... in use today.." {1973)
  9. ↑ http://www.computer.org/csdl/trans/tc/1969/11/01671170-abs.html
  10. ↑ http://research.microsoft.com/en-us/um/people/gbell/CGB%2520Files/Design%2520and%2520Behavior%2520of%2520TSS8%2520IEEE%25206906%2520c.pdf
  11. ↑ p.181,COMPUTER ENGINEERING" (C)'78 by DEC/Digital Press. C.Gordon Bell, J.Craig Mudge, John N. McNamara, ISBN:0-932376-00-2




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