[Coco] Using that 16/32/64 MB RamDrive.

[Gene Heskett]

On Saturday 07 February 2004 15:35, Theodore  Evans wrote:
>On Feb 6, 2004, at 8:58 PM, Paul T. Barton wrote:
>> Robert,
>>
>> I get $03E000 good sectors for a full
>> ~62mb ramdisk. For a size of
>> ($3E000 * 256) 65,011,712 bytes.
>>
>> Also, I noticed that there's no "busy"
>> bit anywhere so it may be disastrous if
>> I go to a second window and do a dir /r0
>> while the first window is writing to /r0.
>> What about V.BUSY can this be
>> used effectively?
>
>I can see why this would seem to be a problem, but assuming that
> this ramdisk is accessed via the RBF man it shouldn't be an issue. 
> It generally isn't on floppy disks and hard drives.  In fact under
> OS-9 I have read a file as it was being written many times.

I think whats being forgotten here is that the os9 framework for a 
file lock is not a whole file lock such as other OS's use, but a raw 
sector number lock asserted on the sector being written.  IMO, the 
best method of all, and one that other OS's don't seem to use.

Like you, I have started an assembly with a file listing option turned 
on, then turned to another screen and "list file" the program is 
generating.  The builtin sector locking assures that the list 
operation, much faster than the assembly, is held until the next 
sector has been written and the lock on it is released.  The list 
operation then tails the write operation by one sector as the 
assembly listing is being generated.

As a matter of fact, I got rather dissappointed in other OS's because 
I couldn't do that, not with amigaos, nor with linux, although I 
haven't really tried that hard or recently in linux.  But, time goes 
only forward.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
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Copyright 2004 by Maurice Eugene Heskett, all rights reserved.