rjchen@phoenix.Princeton.EDU (Raymond Juimong Chen) (02/11/88)
From article <901@cblpe.ATT.COM>, by res@cblpe.ATT.COM (Rob Stampfli): > Does anyone have any information about how robust programs like cpio and > arc are in dealing with these types of problems? if the data error is inside a compressed file, ARC will extract the file and give you a BAD CRC error. If the data error is in the header portion (ie, is in a directory entry) ARC just stops in its tracks and dies. (Which is not unreasonable--the information regarding where the next file is in the archive is kept in the directory entry of the file immediately preceding it. Once you lose one link in the chain, you're a goner.) > Also, not to change the subject, but, > > In article <391@mks.UUCP> alex@mks.UUCP (Alex White) writes: >>Dos: >> A runs to completion: data copied to RAM disk >> Switch to B: data copied from RAM disk to B >>Now, with the assumption of a RAM disk, and one which is large enough >>for your largest pipe [I have about a meg] can anyone think of any reason >>that the dos method should be slower in terms of time-to-complete? >>[Certainly not in terms of time-to-first-output]. If program A accesses the disk while it's doing its thing, then you will gain some speed with the RAM drive. Why? Well, if that is the case, then the disk drive head has to move from the output file to the input file and back again. Even if program A does not access the disk, I believe using the RAM drive will be faster: Unless program A spews out data fast enough, the disk drive motor will probably turn off between writes. You thus lose a second or so every time DOS has to write out a new chunk, waiting for the disk to come back up to speed. Since RAM drives don't have to "come up to speed", there is no loss here. Now, when you copy the file from the RAM disk to the real disk, the COPY program keeps the disk drive motor running pretty much constantly (and besides, COPY uses a larger buffer) you don't lose as much time in terms of waiting for the motor to come up to speed. Agreed, this is probably on the order of seconds, but it's an interesting theoretical question. > I would *love* to know how to tell DOS that I am using a RAM disk, but don't > recall ever reading that this could be done. At least for command.com. I recall seeing exactly such a patch floating around. It involves changing an inquiry as to the current disk drive to loading the number corresponding to the drive you installed your RAM disk on. I'll dig for it and post it if I can find it... -- Raymond Chen UUCP: ...allegra!princeton!{phoenix|pucc}!rjchen BITNET: rjchen@phoenix.UUCP, rjchen@pucc ARPA: rjchen@phoenix.PRINCETON.EDU "Say something, please! ('Yes' would be best.)" - The Doctor