harrow@exodus.dec.com (Jeff Harrow, NCSE LKG1-3/F16 DTN=226-7445) (07/06/86)
Well, I finally got brave and restored my Apple HD20 from a full backup
using HFS Backup from PCPC (1-800-MACBUTT).
Why did I do this: because I wanted to make SURE that this would work as
advertised; because I've been stuck with a particular folder, empty, which
I could NOT trash because, when I tried, it gave me a "Disk Error" alert; and
also because I've always been MISSING some space on my HD20 and really
wanted to get it back (whoever thought that 20 Megabytes wouldn't be
enough...). Here is the problem:
The Finder's window showed 3,272K available, and a GetInfo on the root
folder showed 15,748K in disk for a total of 19,020K accounted for out of
an expected 20 megabytes; 980K missing!! Now, while I expect the file
system, etc. to take up SOME room, .98 Megabytes??!!?? Seems
unreasonable to me.
So, I backed up my 15,748K of data onto 42 single sided floppys (average
374.9K per floppy), using the "check before using" and "check after using"
options in HFS backup. Then, with floppys scattered over my desk, I said a
(temporary, I hoped) goodby to my hard disk and utilized the Hard Disk Test
program on the HD20 Startup floppy to DESTRUCTIVELY test the HD20 (hit a
Command/D at the normal screen to get the more interesting test screen -
but make sure the floppy is NOT write protected or you'll get a bomb when
it tries to write its report).
I let it go through its test (no hard or soft errors) and decided that I
wouldn't find out what had been going on with my wierd folder, so on with
the business of restoring the disk...
I wanted to fully reinitialize the disk to, hopefully, get rid of the last
vestiges of the un-deletable folder, and figured that the destructive
testing of the HD20 (which APPEARED to include an initialize phase) would
render it unreadable to the Mac and would bring up the Initialize dialog box
when the Finder attempted to mount it. Well, I Quit from the Test program
and got the "...slightly damaged... Fix it?" dialog box which causes a
re-build of the desktop file; NOT what I wanted. I thought I'd give it
another try so I said NO, did a Shutdown, and rebooted using the HD20 disk.
This time, when it went to mount the HD20, it did give me the "Initialize"
dialog box, and I said OK.
It initialized fine, but now, here's an oddity (and I'd like some input if you
have some idea of what's going on): Immediately after Initializing my 20
Megabyte HD20, it said 0 Items, 32K in disk, and 19,139K available, for a
total of 19,171K accounted for ON A NEWLY INITIALIZED DISK, leaving 829K
unaccounted for! For the record, the floppy under which I was running at
the time was utilizing FInder 5.0. Any ideas where the missing .829
Megabytes are?
I then went through the HFS Restore-Entire operation (I had the forsight to
put HFS Backup on my HD20 startup disk), all 42 disks, and Yup, my hard
disk was back!
Now, what happend to my disk space? Check this out:
PRIOR TO BACKUP AFTER RESTORE
In Disk 15,748K 14,813K
Available 3,272K 4,207K
----------------------------------------
Total 19,030K 19,050K
Difference from
expected 20MB 980K 950K
OK, now the questions:
o I started with a total of 19,030K accounted for, and ended up with
19,050K accounted for... Where did I pick up the additional 20K?
o I started with one ratio of InUse/Available, and ended up with quite
another ratio (to my advantage; I picked up 935K of Available space, with
the same number of files, and almost the same Total amount of space
accounted for). While I'm quite happy to recover some useable space,
where did it come from?
o WHY is there still a .95 Megabyte difference between the total space
accounted for and the anticipated 20 Megabytes?
Well, while I have generated some questions on which I hope you can shed
some light, this review should also give users of HFS Backup a good feeling
that in the event of a real problem, they can, indeed fully recover their
files from the backup set (and if you DON'T have some form of backup set,
just you wait...).
Disclaimer: I have NO connection with PCPC or Apple except as a usually
satisfied customer.
Jeff Harrowjac@osu-eddie.UUCP (James Clausing) (07/06/86)
In article <4044@decwrl.DEC.COM> harrow@exodus.dec.com (Jeff Harrow, NCSE LKG1-3/F16 DTN=226-7445) writes: >Well, I finally got brave and restored my Apple HD20 from a full backup >using HFS Backup from PCPC (1-800-MACBUTT). (some stuff deleted here) > >Now, what happend to my disk space? Check this out: > > PRIOR TO BACKUP AFTER RESTORE > >In Disk 15,748K 14,813K >Available 3,272K 4,207K > ---------------------------------------- >Total 19,030K 19,050K > >Difference from >expected 20MB 980K 950K > If the disk holds 20,000,000 bytes that is not 20,000K that is only 19,531K now that Apple like everyone else in computer science remembers that K=1024 bytes. That doesn't explain the other 360K missing (from the 19171 given as available after re-initialization) though. Curious. -- ----------------------------------------------------------------- Jim Clausing CIS Department jac@ohio-state.CSNET Ohio State University jac@ohio-state.ARPA Columbus, OH 43210 jac@osu-eddie.UUCP (Disclaimer: Ohio State doesn't have opinions on anything that I have opinions on and if they did I wouldn't claim theirs so why should they claim mine?)
maclab@reed.UUCP (Mac DLab) (07/08/86)
> If the disk (hd20) holds 20,000,000 bytes that is not 20,000K that is only > 19,531K > now that Apple like everyone else in computer science remembers that K=1024 > bytes. That doesn't explain the other 360K missing (from the 19171 given as > available after re-initialization) though. Curious. Pardon my French, but isn't the HD20 20 Megs *Unformatted* ? This would perhaps explain the considerable amount of missing space. Scott
cjn@calmasd.CALMA.UUCP (Cheryl Nemeth) (07/09/86)
The missing .95 megs can be found in Apple's advertising. |-). Actually, the HD20 does not have 20 megs when delivered from the factory. I'm not sure what this is due to (possibily it doesn't use a track, or disk problems ate the rest) but not all hard disks are affected by the same problem. I would guess that the 30k came from icons that were no longer in use and thus were removed from the desktop.
dwb@well.UUCP (07/12/86)
Let us not forget a key point. In the interest of advertising and marketing, most HD manufacturers give the size of the disk before formatting. Depending on how big you make the sectors and other things your effective usage of that space will various quite a bit. They also tend to round the size out to round numbers. By the way, my 40 Meg Hard Disk actually has an extra 128K over 40 Meg of space on it. Sometime you just get lucky I guess. -- David W. Berry dwb@well.uucp dwb.Delphi dwb.GEnie 293-0544.408.MaBell DOWN WITH FASCIST APPLE!
phil@sivax.UUCP (07/16/86)
> Let us not forget a key point. In the interest of advertising > and marketing, most HD manufacturers give the size of the disk before > formatting. Depending on how big you make the sectors and other things > your effective usage of that space will various quite a bit. They > also tend to round the size out to round numbers. > > By the way, my 40 Meg Hard Disk actually has an extra 128K over > 40 Meg of space on it. Sometime you just get lucky I guess. > -- My 20 meg Micah Drive has 22.4 meg formatted on it. Sometimes you get REALLY lucky!!!!! Phil Hunt calma!sivax!phil