Gerhard Postpischil wrote:
On 7/20/2010 11:01 AM, Edward Jaffe wrote:
I've seen other "old" programs with many hard-coded offsets and
lengths and always wondered why this was such common practice
back then.
Was it because there were a lot of inexperienced assembler
programmers writing code? Was it because people thought the
platform would not last and treated every program as a "throw
away"? Was it due to limitations in the assembler itself?
In addition to all the other reasons, I'd suggest two more. One was
the belief that IBM wouldn't change the offsets, the other that in the
days of mountable DASD, SYS1.(A)MODGEN just wasn't accessible most of
the time. We also ordered IBM optional source, and extracted the
macros (SYS1.PVTMACS), and those also wasn't resident until the seventies.
A lot of these programs (e.g., TSSO) have hard-coded offsets and lengths
to their own data areas -- not just IBM's.
--
Edward E Jaffe
Phoenix Software International, Inc
831 Parkview Drive North
El Segundo, CA 90245
310-338-0400 x318
edja...@phoenixsoftware.com
http://www.phoenixsoftware.com/
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