[Info-vax] Example of random access by record number on an RMS fixed record size, relative organization file?

[Arne Vajhøj]

On 9/21/2023 8:19 AM, bill wrote:
> On 9/20/2023 8:07 PM, Arne Vajhøj wrote:
>> On 9/20/2023 12:23 PM, bill wrote:
>>> Funny thing about this.  I found very little about it in any of
>>> the (many) COBOL books I have.  I also don't remember ever having
>>> done it in a production program in my entire 40 year career.
>>> This kind of task was done much better with ISAM and today it
>>> would be database.
>>
>> I don't think relative files has been big anywhere anytime.
>>
>> But it is supported in the Cobol standard.
>>
>> I don't see any point of relative files in newer times, but
>> I suspect that going sufficiently long time back there were
>> performance reasons to prefer relative over indexed/ISAM
> 
> While ISAM may be less efficient relative files can waste a
> lot of space.  Space is allocated for empty records and back
> in the good ole days disk space was premium and very expensive.

True. Relative files only makes sense if keys does not have
too much holes. As usual there are tradeoffs.

Arne