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

[Arne Vajhøj]

On 9/21/2023 6:12 PM, Arne Vajhøj wrote:
> On 9/21/2023 1:10 PM, gah4 wrote:
>> On Thursday, September 21, 2023 at 5:19:50 AM UTC-7, bill wrote:
>>> 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.
>>
>> Relative files are convenient if your numbering system is already
>> not sparse.
>>
>> Otherwise, it is usually to make it a hash table, and hash the
>> index before using it to read/write a record.
> 
> A hashing producing non sparse results will typical also
> produce a lot of collisions requiring collision handling.

That was not accurate described.

Any hashing requires collision handling, but hashing
producing lots of collisions requires clever collision
handling that does not kill performance.

Arne