System Support Program

System Support Program (SSP) was an operating system for the IBM System/34 and System/36 minicomputers. SSP was a command-based operating system released in 1977.

SSP originally contained 60 or so commands that were implemented on the System/34 from 1977 to 1983 in different versions called releases. Release 1 was issued with the original S/34 in 1977. Release 9 was issued in 1981. In 1983, IBM repackaged SSP on a new computer called the IBM System/36, which was not object-code compatible with the S/34. In 1994, IBM repackaged SSP on an updated model of the S/36 called the Advanced/36. The A/36 was an IBM AS/400 which had the SSP implemented as a "virtual machine".

Major releases of SSP include:

Limitations on S/36 and A/36 and M/36 operating system: The maximum amount of disk space that a system could utilize was 4 gb (per occurrence of the operating system, so a machine running two M36 "partitions" could have 4 gb in each. Another limitation was the program size, could not exceed 64kb (not 64mb, but 64KB). If you had a program that was larger than that, you had to become creative in the later years when call/parm came into place, as you would move code into a called program, because if the base program was 63kb for example, you could easily call a 20kb called program. You also could not have more than around 8,000+ files on the machine. There were also restrictions on the number of files you could bring into a program (again, you could get around by putting files in called programs and passing the result back in. The maximum number of records you could initially load was about 8 million and the maximum a file could hold was about 16 million. None of these limitations exist in S36EE (there are a few maximum number of files in a program, but much larger# than in native SSP).

Using SSP, the operator can create, delete, and manage S/34-36 objects such as libraries, data files, menus, procedures, source members, and security files.

SSP contains modules such as DFU, SEU, SDA, and WSU that permit operators to build libraries and files, enter information into those files, produce simple reports, and maintain a menu structure that simplifies access to the information. The Advanced/36 does not support WSU. Password and resource security are also implemented through SSP, as are remote communications, which today is similar to dial-up networking.

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