[Coco] Segment List Full on backup

[Gene Heskett]

On Tuesday 27 January 2015 20:37:56 Allen Huffman did opine
And Gene did reply:
> > On Jan 27, 2015, at 4:56 PM, Gene Heskett <gheskett at wdtv.com> wrote:
> > 
> > I was not aware that we had a backup program that functioned like dd
> > does on linux other than the backup that is part of the os9 cmds
> > available. And it demands identically formatted disks as its safety
> > mechanism.
> 
> Yes, it’s not like DD. It does sector-by-sector (so it copies
> “unusedâ€‌ sectors), but it does match LSN0 first. I have a program
> that reads LSN0 off of the source device, then writes it to my blank
> .DSK image. Boom! Instant backup-friendly destination ;-)
> 
> > Does this "backup" program you refer to actually clone one complete
> > disk to another, effectively making a carbon copy of the original? 
> > IOW, are you using the backup from the nitros9 cmds tree?
> 
> Yes, Microware “backupâ€‌ or whatever is in NitrOS-9.
> 
> > The os9 backup command is the only command in the box that does that.
> > neither BRU nor Backar do that. But backar is what got me into
> > trouble as it needs a single bit, someplace in the fd.sector to
> > function as intended. But every bit is already spoken for. So I'll
> > just drop backar until such time as I can come up with a fix that
> > works.
> 
> I ran in to issues reading an OS-9 EZ135 disk on my old PC laptop for
> the same reason. I wrote a similar program to save the OS-9 LSN0, then
> I copied over a PC EZ135 LSN0 to the OS-9 disk. After that, I was able
> to access it from a DOS C program. Seems like the BIOS must look at
> the disk too — if it doesn’t look valid, I couldn’t access it.
> But this was back in the 90’s. Maybe DOS has changed.
> 
> > So what I do, and not nearly often enough, is dsave the operating
> > drive to a subdir on the second drive as I have 2 identical 1Gb scsi
> > drives, and with what I have on the main drive, I could setup at
> > least 5 such subdirs on the second drive if I needed multiple
> > generations for mistake recovery.
> 
> Yeah, in my case, I want all the sectors. I want to preserve any
> deleted files, etc. that I may want to go peek at. A full clone of
> what I had that last time I used the system.
> 
> > How much data is there? That FAT/DAM limit of $FFFF, translated to
> > bytes assuming a 1 sector cluster, is 134,215,680 bytes.  A full
> > EZ135 might be able to exceed that but I'd have reservations it
> > could based on the Seagate marketing depts legendarily wishful
> > thinking.
> 
> The EZ135 capacity, based on what the old SCSI query command returned,
> was right on the money for 128MB. 128MB compact flash cards, however,
> are not (1000 byte Ks).
> 
> > FWIW, I have an LS-120 drive and a 6 pack of disks for it, but have
> > never acquired the IDE interface it needs.  I should do that when it
> > becomes available again.
> 
> I just noticed SuperIDE was no longer available. No wonder folks have
> been buying up the Glenside boards.

I was under the impression that somebody had made another run of those 
boards a few months back.  Or was I dreaming?

> >> I think RBF is returning it because the sector exceeds the number of
> >> clusters that the DAM ($FFFF * 8 = 524,280) supports.
> > 
> > Now that is a possibility. It is also possible that os9 ran out of
> > bits in the LSN# issued, but since that number is in LSN's, not
> > bytes, its well north of 3.5Gb by then.  So I can't see that
> > occurring.
> 
> Yeah, in this case, once it reads LSN0 it shouldn’t care. I *think*
> what I did was give it too many sectors ($7FFFF) — when it only
> reads to 0x7FFF8. This would explain why BACKUP failed, and a normal
> GET/PUT in BASIC09 did at the end sector (524,287).
> 
> I should really go back and read all my old EZ135 articles. I dove in
> to all of this. But, relearning is fun!
> 
> 		— A

I do that myself from time to time. At 80, my memories from 2 decades back 
are clearer than what I did last week, and it can get frustrating.

Cheers, Gene Heskett
-- 
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