TSX-Plus
{{Short description|Software}}
{{Infobox OS
| name = TSX-Plus
| logo =
| logo caption =
| logo size =
| logo alt =
| screenshot =
| caption =
| screenshot_size =
| screenshot_alt =
| collapsible =
| version of =
| developer = S&H Computer Systems
| family =
| working state =
| source model =
| released =
| discontinued =
| RTM date =
| GA date =
| latest release version =
| latest release date =
| latest preview version =
| latest preview date =
| marketing target =
| programmed in =
| language = English
| update model =
| package manager =
| supported platforms = PDP-11/LSI-11
| kernel type =
| userland =
| ui =
| license = Proprietary
| preceded by =
| succeeded by =
| website =
| support status =
| other articles =
| prog_language =
}}
TSX-Plus is a multi-user operating system for the PDP-11/LSI-11 series of computers. It was developed by S&H Computer Systems, Inc. and is based on DEC's RT-11 single-user real-time operating system (TSX-Plus installs on top of RT-11).
Overview
The system is highly configurable and tunable.{{Fact|date=February 2007}}
Due to the constraints of the memory management system in the PDP-11/LSI-11, the entire operating system core must occupy no more than 40 kibibytes of memory, out of a maximum possible 4 mebibytes of physical memory that can actually be installed in those machines (mandated by the 22-bit address space). The strength of TSX-Plus is to simultaneously provide to multiple users the services of DEC's single-user RT-11.{{cite magazine
|magazine=Hardcopy |title=The RT-11 Perspective
|date=January 1985 |page=125 |author=Milton Campbell}} Depending on which PDP-11 model and the amount of memory, the system could support a minimum of 12 users{{cite news
|newspaper=Computerworld |title=S&H TSX-Plus on 11/23, 11/34
|quote= efficient, general-purpose timesharing for up to 20 users on 11/23 and 11/34 based ...
|date=December 1, 1980 |page=67}} (14-18 users on a 2Mb 11/73, depending on workload). A productivity feature called "virtual lines" "allows a single user to control several tasks from a single terminal."{{cite magazine |magazine=Hardcopy |date=October 1982 |page=9 |title=TSX-Plus: Time Share RT-11}}
The software included a WP package named Lex-11See Tom Barnard and Ace Microsystems, Australia. New Scientist, 5 May 1983, Vol 98, No 1356, in Google Books. and a spreadsheet from Saturn Software. The machine slowed considerably if more than 8 students wanted to use the word-processing package at the same time. There was also a decision-table language called "D" from the NCC in Manchester which worked very well on TSX Plus.
History
Released in 1980, TSX-Plus was the successor to TSX, released in 1976. The system was popular in the 1980s. The last version of TSX-Plus had TCP/IP support.
S&H wrote the original TSX because "Spending $25K on a computer that could only support one user bugged" (founder Harry Sanders); the outcome was the initial four-user TSX in 1976.
Bootstrapping
{{unreferenced section|date=October 2022}}
TSX-Plus required bootstrapping RT-11 first before running TSX-Plus as a user program. Once TSX-Plus was running, it would take over complete control of the machine from RT-11. It provided true memory protection for users from other users, provided user accounts and maintained account separation on disk volumes and implemented a superset of the RT-11 EMT programmed requests. RT-11 programs generally ran, unmodified, under TSX-Plus and, in fact, most of the RT-11 utilities were used as-is under TSX-Plus. Device drivers generally required only slight modifications.
See also
References
{{Reflist}}
External links
- [https://web.archive.org/web/19961209114726/http://sandh.com/ S&H Homepage]
{{Operating system}}
Category:Proprietary operating systems
{{operating-system-stub}}