mike@scomp.lancashire-poly.ac.uk (Mike Higgs) (06/09/90)
Hi, I was wondering if when using tar piped to vol, you could insert compress into the command line i.e. tar | compress | vol. Can anybody see a reason why this wouldn't be OK? Mike Higgs mike@uk.ac.lancsp.sc School of Computing, or higgs_m@uk.ac.lancsp.p1 Lancashire Polytechnic, Preston, PR1 2TQ. U.K. Tel. +44 0772 201201 ext.2225
nick@ultima.cs.uts.oz (Nick Andrew) (06/15/90)
mike@scomp.lancashire-poly.ac.uk (Mike Higgs) writes: >Hi, > I was wondering if when using tar piped to vol, you could insert >compress into the command line i.e. tar | compress | vol. > Can anybody see a reason why this wouldn't be OK? ( Obviously the inverse is vol | uncompress | tar ) It works fine, so long as one condition is noted - that TAR knows when the end of its input has been reached, without reading EOF. Standard Vol merely blurts out the entire contents of the disk (and would keep doing so forever unless tar breaks the pipe). For this reason, "compress | vol" won't work. (I.E. say you had a huge file, NOT a tarfile). Compress does not know when its input is finished, so piping the data back (vol | uncompress) will result in junk at the end of the output. All the above is merely a blatant plug for my own version of VOL, which has these features: * Knows how long its input is, so output == input * Keeps at the front of each diskette, * Magic number * Creation timestamp * Diskette number within set * Length of data on the diskette * You can query the creation time of any volume set * Has checks to ensure the user doesn't shoot hisself in the foot * Inserting disks in the wrong order * Overwriting a volume of the same set * Trying to read a volume of a different set * Can read & write disks compatible with original Vol * Verbose mode Now that I've whetted your appetite, where do you get it?? I'll post it to the net in a few days. Note longtime Minix'ers ... I posted a similar Vol many months ago; this version has been considerably cleaned up, bugs removed, and timestamp query added. Regards to all, Nick. -- ACSnet: nick@ultima.cs.uts.oz UUCP: ...!uunet!munnari!ultima.cs.uts.oz!nick