[comp.sys.mac.programmer] read,ASYNC

hedley@iitinc (Hedley Rainnie) (06/01/91)

Hello. A coworker and I are trying read,ASYNC and find that it behaves
like regular read. How we determine that is by reading a large block
from a file and the call doesn't return until a lot of disk activity 
completes. I can understand that on a cheap mac maybe the two could be
the same but this in on a IIfx. I havn't found a reasonable def'n of
what read,ASYNC will do for me, I had hoped to get a non-blocking file
read. Has anyone found a way to get a non-blocking file read? 

Thanks, Hedley
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REEKES@applelink.apple.com (Jim Reekes) (06/02/91)

In article <178@iitinc.UUCP>, hedley@iitinc (Hedley Rainnie) writes:
> 
> Hello. A coworker and I are trying read,ASYNC and find that it behaves
> like regular read. How we determine that is by reading a large block
> from a file and the call doesn't return until a lot of disk activity 
> completes. I can understand that on a cheap mac maybe the two could be
> the same but this in on a IIfx. I havn't found a reasonable def'n of
> what read,ASYNC will do for me, I had hoped to get a non-blocking file
> read. Has anyone found a way to get a non-blocking file read? 

HFS is asychronous, but the SCSI Manager is not.  So reading from a SCSI
disk will always be done synchronously.  Floppies and servers do read/write
asychronously.

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