[Info-vax] C... the only winning move is not to play...

[Johnny Billquist]

On 2014-02-13 23:06, VAXman- @SendSpamHere.ORG wrote:
> In article <ldjc2s$f1b$1 at dont-email.me>, David Froble <davef at tsoft-inc.com> writes:
>> {...snip...}
>>
>> What I meant was the data is read into an internal I/O buffer, and the
>> desired data record is then moved into a user's pre-defined record
>> buffer.  In a write of the data record, RMS moves it back into the
>> internal I/O buffer, then writes the I/O buffer.
>>
>> If the data in the I/O buffer is locked, then is should not be stale.
>
> OK.  I reread.  You were talking about the locate and move modes of the RMS
> buffers.  Locate mode is only valid using a $GET and it's unavailable when
> the record crosses a block boundary, file access is set UPDATE, compressed
> records (in the case of indexed files), global buffers have been specified
> or multiple streams access the file.

Really? Are locate mode not available for writes in VMS. They are in 
RSX. When you open the file, you tell what the maximum size you might 
write is, and RMS will return a pointer to where you should be writing 
your data. It might be a bounce buffer, but it might also be the actual 
disk buffer directly.
And each $PUT will update the write pointer for the next write to be done.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol