Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!sdrc!thor!scjones From: scjones@thor.UUCP (Larry Jones) Newsgroups: comp.binaries.ibm.pc.d Subject: Re: Why load "SHARE" (was Re: program to break 32MB barrier) Message-ID: <145@thor.UUCP> Date: 30 Jan 91 21:50:38 GMT References: <1991Jan21.230226.4874@hub.cs.jmu.edu> <5489@husc6.harvard.edu> Distribution: comp Organization: SDRC, Cincinnati Lines: 33 In article , otto@tukki.jyu.fi (Otto J. Makela) writes: > In article <140@thor.UUCP> scjones@thor.UUCP (Larry Jones) writes: > SHARE is needed to allow the old DOS 1.0 FCB functions to work right > on a large partition -- if it is not loaded, they wrap around and trash > the partition. Since they are significantly faster in some cases than > the newer functions that were supposed to replace them, they are still > widely used. If you have a large partition and don't load SHARE, you're > living on borrowed time. > > Does this mean that the COMMAND.COM delete command will trash the hard disk > if SHARE is not loaded ? And they don't say this in the manual ? Well, the manual DOES say you need to load SHARE for >32M disks, although it sure would have been nice if it had explained WHY! The problem with FCBs is that, without share, any attempt to read or write past the 32M line wraps around to the beginning of the disk instead. A delete operation only writes the FAT and the directory, not the actual data. The FAT is always near the beginning of the disk, so it should always be below 32M. I would guess that most directories are too, although you certainly should be able to create a subdirectory above 32M. I don't know if that would cause delete to misbehave or not -- perhaps the FCB delete function doesn't use the FCB read and write functions to do it's work?!? On the other hand, what about those people with NOSHARE loaded instead of SHARE (NOSHARE intercepts the FCB function calls and returns a failure status) -- do wildcard deletes stop working, does NOSHARE not trap the FCB delete, or does the FCB call failure cause it to fall back and use the handle functions instead? ---- Larry Jones, SDRC, 2000 Eastman Dr., Milford, OH 45150-2789 513-576-2070 Domain: scjones@thor.UUCP Path: uunet!sdrc!thor!scjones You don't get to be Mom if you can't fix everything just right. -- Calvin