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From: Spriggly on 30 Sep 2009 21:27
Does anyone know where i can find info on CMD boot ROM's? I have a CMD
20 that has a v2.52 boot ROM and was wondering the limitations of this
ROM as far as how big a drive it can "see." Also, lets say it can only
see 200 MB can I still use a 1GB drive, but it will only use 200MB?
Has anyone tried this and can anyone point me to some docs?

Thanks in advance.
From: Jim Brain on 30 Sep 2009 23:43
Spriggly wrote:
> Does anyone know where i can find info on CMD boot ROM's? I have a CMD
> 20 that has a v2.52 boot ROM and was wondering the limitations of this
> ROM as far as how big a drive it can "see." Also, lets say it can only
> see 200 MB can I still use a 1GB drive, but it will only use 200MB?
> Has anyone tried this and can anyone point me to some docs?
>
> Thanks in advance.
If you want a 2.80 bootrom to alleviate the concerns, let me know. I
have a HD-40 here and can create an EPROM for you.

Jim
From: Mr. X on 1 Oct 2009 16:43
"Spriggly" <spriggs.d(a)gmail.com> wrote in message
news:9f7d7248-9ba0-4694-a44a-33d69041a275(a)c28g2000yqd.googlegroups.com...
> Does anyone know where i can find info on CMD boot ROM's? I have a CMD
> 20 that has a v2.52 boot ROM and was wondering the limitations of this
> ROM as far as how big a drive it can "see." Also, lets say it can only
> see 200 MB can I still use a 1GB drive, but it will only use 200MB?
> Has anyone tried this and can anyone point me to some docs?

I don't know the breakdown by ROM version but some people got as much as 254
partitions of 16M each for a total of about 4G.

That's the limit for transparent CBM kernel addressing being 254 virtual
drives of 256 tracks of 256 sectors of 254 bytes (first 2 bytes of each
sector link the next track/sector for this file chain in file mode).

SCSI drives use a virtual block address system so in theory it should work
with larger drives but I don't know of anyone who has actually tried it.

CMD manual scans here:
http://www.zimmers.net/anonftp/pub/cbm/manuals/cmd/index.html

There are several smaller, faster & more reliable (but less compatible) new
FlashRAM based products for the C64 now so before you put much money into an
old CMD HD (ROM, drive, etc), you might consider one of the new toys with
removable Flash. Some of them even have ethernet and other features.


X


From: Spriggly on 2 Oct 2009 20:10
Thanks for your suggestions.
I thought I would report back on how it went. My CMD HD 20 went out
after 15 or so years of service. To replace it I found a SCSI drive
from an old server. Its a 9 GB segate 7200 rpm. I put it in and ran
LLFORMAT, no problem there. I then ran CREATESYS and that worked great
too (gotta love CMD stuff). Turns out that with my boot ROM v2.52 and
then the HD DOS v1.80 the drive is 600 MB. Not bad considering the one
that went bad was 20 MB, a nice little upgrade. I will never use 600
MB on the c64 so it's good enough for me. And the 7200 rpm drive is
REALLY fast, stuff loads twice as fast as the old HD!

Thanks.
From: stiggity on 9 Oct 2009 11:18
On Oct 2, 8:10 pm, Spriggly <sprigg...(a)gmail.com> wrote:
> Thanks for your suggestions.
> I thought I would report back on how it went. My CMD HD 20 went out
> after 15 or so years of service. To replace it I found a SCSI drive
> from an old server. Its a 9 GB segate 7200 rpm. I put it in and ran
> LLFORMAT, no problem there. I then ran CREATESYS and that worked great
> too (gotta love CMD stuff). Turns out that with my boot ROM v2.52 and
> then the HD DOS v1.80 the drive is 600 MB. Not bad considering the one
> that went bad was 20 MB, a nice little upgrade. I will never use 600
> MB on the c64 so it's good enough for me. And the 7200 rpm drive is
> REALLY fast, stuff loads twice as fast as the old HD!
>
> Thanks.

So what determines the maximum _recognized_ storage space? the
boot-rom, or the HD DOS? I would assume the boot rom. My connor 20mb
unit went out, and i replaced it with an IBM 4gb SCSI drive, and after
doing
a create-sys i was able to recognize 583MB and i have a version 2.6
boot rom.
I guess to recognize higher than 600mb one would need the version 2.8
boot rom.
My drive was sold as an HD100 with a 170mb mechanism, which was
swapped out
for an ancient connor 20mb unit. thanks,.

-Steve
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