31 Aug
2005
31 Aug
'05
10:41 a.m.
On Wed, 31 Aug 2005 09:53:55 -0400, Paul Koning
<pkoning at equallogic.com> wrote:
I don't know about Modcomp, but that's not the
IBM way. IBM had
amazingly primitive file systems (at least through OS/360), but not
quite *that* primitive. You could create files at anytime, but only
through JCL. (Actually, I think it was possible to create files under
program control, but not via the standard APIs.)
[...]
paul
You are talking about big iron here. The IBM 1800, SEL, and Modcomp
were essentially toys which used a preallocated file system to ensure
speed in file access. All files were guaranteed contiguous and of
know size. The editor, compiler, and linker each had their own
segments which they individually managed. The editor would create
"files" within its segment. The JCL on these machines was quite
rudimentary and did not include any capability to re-hack the file
system. You could always design an application to partition and
manage one of the preallocated segments.
I remember having to re-sysgen the system numerous time while we were
designing the application in order to optimize the file sizes.
CRC