IBM System/36
<computer> A mid-range computer introduced in 1983, which remained
popular in the 1990s because of its low cost and high performance. Prices
started in the $20k range for the small 5362 to $100+k for the expanded 5360. In
1994, IBM introduced the Advanced 36 for $9,000.
The largest 5360 had 7MB of RAM and 1432MB of hard disk. The smallest 5362 had
256K of RAM and 30MB of hard disk. The Advanced 36 had 64MB of RAM and 4300MB of
hard disk, but design issues limit the amount of storage that can actually be
addressed by the operating system; underlying microcode allowed additional RAM
to cache disk reads and writes, allowing the Advanced 36 to outperform the S/36
by 600 to 800%.
There was only one operating system for the S/36: SSP (System Support Product).
SSP consumed about 7-10MB of hard drive space. Computer programs on the S/36
reside in "libraries," and the SSP itself resides in a special system library
called #LIBRARY.
Components of SSP include the Data File Utility (DFU), the Source Entry Utility
(SEU), the largely obselete Work Station Utility (WSU), the Screen Design Aid
(SDA) and Operational Control Language (OCL).
Using the IBM S/36 is relatively simple. The operator sits in front of a
computer monitor, types on a keyboard, and interacts using a series of on-screen
forms. S/36 is command-oriented, like MS-DOS, however, S/36 additionally uses
more than 70 menus which allow operators to type the number of an appropriate
command or response, and application writers can create their own menus and
commands ("procedures.")
Programmers use SEU to create or modify a source program which is then compiled
into an object program. SEU uses 50 or so templates to assist the operator with
the syntax of different types of sources.
By 1985, an application called Programmer/Operator Productivity was widely
available and was probably the most popular (and pirated) S/36 software ever
written. POP included a full-screen editor called FSEDIT which could be used in
place of SEU, which only allowed single-line editing.
Data File Utility allows the programmer to quickly create a simple,
single-record display program to add, update and delete records within a file.
Also, simple report programs can be created.
Screen Design Aid allows the programmer to create menus, create and update
simple forms which are called "display formats" or "prompt screens", and view
existing display formats.
By using Operational Control Language, the programmer can assign files and
resources to a particular program and pass run-time information like a
processing date, order number, or user name to the compiled program. Programs
can acquire up to 8 workstations, or run in the background, but usually they run
on only one workstation. The largest program size is 64K.
Whenever a program is called, SSP searches in the named user library and then
#LIBRARY. Therefore, a system program can be called from any library and all
users have access to it.
S/36 has three types of security: (1) password security, (2) a badge reader
option that almost no-one ever bought, and (3) resource security. There are five
levels of users access and five levels of resource access. By using password and
resource security effectively, the administrator (who was at that time often
called a DP Manager or Information Systems Manager) can restrict access to
critical and secure applications.
The cheapest, and therefore most popular, language compiler for the S/36 is RPG
II, a language based on fixed logic cycles which arose in the days of card
readers. Other languages include COBOL, FORTRAN and BASIC. Almost every S/36
shop with in-house design uses RPG.
It's interesting to note that the S/36 allows the operator to change a program
while it is being used, which can be very dangerous on live data. The S/38 and
the iSeries computer do not allow this.
IBM has not marketed the S/36 or Advanced 36 since 2000. Price/performance of
the AS/400 (aka iSeries) and hardware technology of the present-generation PC
makes the S/36 a much less attractive offering from a different era in
computing.
(2005-04-05)
Nearby terms:
IBM PC AT « IBM PCjr « IBM PC XT « IBM System/36
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