[Info-vax] wrong file format

[Dirk Munk]

Hein RMS van den Heuvel wrote:
> On Saturday, January 2, 2021 at 11:01:12 PM UTC-5, Craig A. Berry wrote:
>> On 1/2/21 8:04 PM, Arne Vajhøj wrote:
>>> On 12/31/2020 10:54 PM, Bill Gunshannon wrote:
> 
>>> * the traditional story is that all language RTL IO goes
>>> through RMS - including C RTL (even though that one
>>> supposedly is a bit more complicated than other
>>> languages)
> 
> Last century, yes.
> Today for the simple sequential file COBRTL, CRTL and SORT switched away from record IO to roll their own with BlockIO ($READ, $WRITE).
> I don't recall them doing direct $QIO calls. BlockIO is a tiny layer over QIO adding error handling mostly.
> Record IO is way to expensive for high volume IO - going in and out of exec mode 'all the time', probing the argument blocks and buffers and so on.
> Block IO incurs this overhead typically much less frequently to the point where it does not really matter ( 10 ...  50 times less is my guess).
> 
> It's all easy enough to verify for your exact situation with a tiny program doing the IO calls you would like to understand.
> Code in a pause after a few IOs and activate ANALYZE /SYSTEM ... SET PROC ... SHOW PROC/RMS=(RAB,FAB,BDBSUM[,IFAB,IRAB,FSB])
> 
> Hein
> 
That switch must have been a long time ago for COBRTL. As long as I can 
remember COBOL on RSX and VMS had the "reserve nn areas" in the File 
control paragraph of the Input-output section of the Environment 
division. to speed up file access, and that made IO much faster. As far 
as I know that clause reserved nn blocks for that file.