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- Path: sparky!uunet!cs.utexas.edu!swrinde!gatech!rutgers!ub!dsinc!bagate!cbmvax!cbmehq!cbmger!edohwg!heinz
- From: heinz@edohwg.UUCP (Heinz Wrobel)
- Newsgroups: comp.os.os2.misc
- Subject: Re: DOS and OS/2 *Already* are Case sensitive!!!
- Message-ID: <heinz.02os@edohwg.UUCP>
- Date: 27 Jul 92 00:46:57 GMT
- References: <5y!mdjh.feustel@netcom.com>
- Organization: Edotronik GmbH
- Lines: 62
-
- In article <5y!mdjh.feustel@netcom.com> feustel@netcom.com (David Feustel) writes:
- >Both Dos and OS/2 already are case sensitive since filenames can be
- >stored in directories as lowercase. it's just that the
- >existing underlying case sensitivity is not handled consistently.
-
- They are not "sensitive", they are "preserving". The difference is that
- HPFS DOES NOT CARE about case. It just leaves those nice looking letters in
- there that you have nice looking filenames. If case really mattered then it
- would be case "sensitive".
-
- >Providing a switch "DUAL_CASE=[Y|N]" that enables/disables mapping of
- >characters to uppercase before name comparisons in DosFindFirst and
- >DosFindNext would let everyone use/not use this feature as they
- >please.
-
- How could you ever switch? There's just NO WAY TO PUT A CASE SWITCH INTO A
- FILESYSTEM LIKE HPFS. Let's say you have a >300MB HD in your business in
- some network environment with a case "sensitive" filesystem. You'll never
- know if you have conflicting filenames somewhere, e.g. "ReadMe" and
- "README". Then you switch back to the case preserving mode and all of a
- sudden the filesystem will get rather confused. "ReadMe" and "README"
- should be the same now!? The technical explanation is:
-
- a) Two filenames that are in the same directory would suddenly be
- identical.
- Option 1: One file will be inaccessible forever.
- Option 2: You'll never know which one the filesystem finds.
- Option 3: The filesystem gets confused and dies.
-
- b) Inside the filesystem hash codes are computed for each filename and
- if it is a good filesystem those hash chains are sorted in a
- reasonable way. Change the hash criteria and you'll die.
-
- c) Try to backup this directory with "ReadMe" and "README" onto a
- floppy and move it to your friends desktop computer. Which file will
- he get if he is not case sensitive? BTW, can you handle floppies
- formatted with a case sensitive filesystem?
-
- The only way would be to create a new 'type' of HPFS (let's call it HPFSC)
- that is case "sensitive" instead of just being case "preserving". Which
- incidently leads to a backup-reformat-restore cycle if you want to switch.
-
- THERE CANNOT BE ANY REASONABLE WAY TO CHANGE ON THE FLY FOR A TODAY'S
- DESIGN OF A FILESYSTEM.
-
- You can always switch from case "preserving" to sensitive automatically,
- but if you think about it, you can't go the other way if you don't want to
- change your occupation to "filename checker". ;-)
-
- BTW, if I'm wrong please email me. I'll be glad to summarize. But really, I
- don't think I'm wrong. I've been using case "preserving" filesystems since
- 1986 and non preserving one's some years longer like many others. ;-) :-)
-
- >Dave Feustel N9MYI <feustel@netcom.com>
-
- --
- Heinz Wrobel, Edotronik GmbH (ECG018)
- FAX +49 89 850 51 25 / TEL +49 89 850 25 20 (HOME!&VOICE, sometimes...)
- Path: cbmehq!cbmger!edohwg!heinz@cbmvax.commodore.com
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