Editing IBM System/36 (section)

===Memory and disk===

The smallest S/36 had 128K of RAM and a 30 MB hard drive.

The largest configured S/36 could support 7MB of RAM and 1478MB of disk space. This cost over US$200,000 back in the early 1980s. S/36 hard drives contained a feature called "the extra cylinder," so that bad spots on the drive were detected and dynamically mapped out to good spots on the extra cylinder. It is therefore possible for the S/36 to use more space than it can technically address. Disk address sizes limit the size of the active S/36 partition to about 2GB; however, the Advanced/36 Large Package had a 4GB hard drive which could contain up to three (emulated) S/36s, and Advanced/36 computers had more memory than SSP could address (32MB to 96MB) which was used to increase disk caching.

Disk space on the System/36 was organized by ''blocks'', with one block consisting of 2560 bytes. A high-end 5360 system would ship with about 550,000 blocks of disk space available. System objects could be allocated in blocks or records, but internally it was always blocks.

The System/36 supported [[memory paging]], referred to as "swapping".<ref>{{cite web|url=http://bitsavers.org/pdf/ibm/system36/SC21-9019-5_System_36_Concepts_and_Programmers_Guide_198706.pdf|title=System/36 Concepts and Programmer's Guide|date=June 1987|access-date=2021-05-01|publisher=IBM}}</ref>