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

[Gene Heskett]

On Friday 06 February 2004 00:11, Theodore  Evans wrote:
>On Feb 5, 2004, at 6:42 PM, Gene Heskett wrote:
>> On Thursday 05 February 2004 23:28, Paul T. Barton wrote:
>>> Mark,
>>>
>>> Gee, I don't know. I'll try and dsave
>>> my biggest partition to /r0 and see.
>>>
>>> Formatting is really a pain. For now
>>> I have 15.9MB and formatting counts
>>> from $000 to $3DF. iIt takes about
>>> 3-4 minutes. The actual dsave-copy is
>>> pretty fast.
>>>
>>> I wish that I had another version of FORMAT
>>> just for this ramdrive that wouldn't print
>>> the sector #'s and "run faster".
>>
>> Can you set it for logical only, with no verify?  Unless its
>> verifying, which is where the sectors get counted up, a logical
>> format should only take a few milliseconds.  It only has to
>> compose and write 3 sectors to do that, LSN0 for the usual
>> reasons, LSN1 for the fat, and LSN2 for the first sector of the
>> root directory. Everything else gets written as needed anyway.
>
>A 16 MB drive would have 64k 256 byte sectors which would require an
>allocation map (it isn't a FAT as is only indicates which sectors
> are allocated, not how they are structured as files like the chains
> in MS-DOS/Windows)  of 8k bytes or 32 sectors, so even a logical
> format of a drive this size would require writing 34 sectors. 
> Still mighty fast. Even a drive as small as a 720k floppy requires
> more than a single sector for the allocation map.

All true of course.  And myram does extend the fat to fit the size its 
set for via the cyl= in dmode, so if set for 1.5 megs, it does have 
to write a few more sectors of zeroed fat before it can write the 
root dir's first sector and LSN0.  But thats still so quick, less 
than 200 milliseconds, that its a never mind...  Megaread times on a 
nitros9 machine are a slightly fat 11 seconds, same as for a scsi 
disk since the transfer time is set by the coco's PIO(0) effective 
mode.  If the i/o mechanism were extended to use the other, nocan 
mode of switching pages, I doubt if the slowdown would be all that 
detectable.

-- 
Cheers, Gene
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Copyright 2004 by Maurice Eugene Heskett, all rights reserved.