pb@idca.tds.PHILIPS.nl (Peter Brouwer) (08/31/90)
In article <3295@segue.segue.com> jim@segue.segue.com (Jim Balter) writes: >In article <628@ssp2.idca.tds.philips.nl> pb@idca.tds.philips.nl (Peter Brouwer) writes: >>To be precise, the gap determines the way the free block space is organised. > >That is neither precise nor correct. The gap is the rotational gap, >which is the offset between the logical track start from one track to another. >This offset is to account for track-to-track seek time; if it is just right, >the next block will be under the read head just as it settles over the track. >It has nothing to do with free space, unless your system has taken this value >over for something other than its original purpose. The gap was important >back when UNIX ran off of RK05's; modern disk controllers should optimize >track formatting for contiguous I/O. I think you are confused by the term gap. It is also used in disk format layout definitions. In unix it has the meaning as I described it. Info was retrieved from the sources of mkfs and fsck. -- # Peter Brouwer, | Philips Information Systems, # # NET : pb@idca.tds.philips.nl | Department P9000-i Building V2, # # UUCP : ....!mcsun!philapd!pb | P.O.Box 245,7300AE Apeldoorn,The Netherlands# # PHONE:ext [+31] [0]55 432523, | FAX :ext [+31] [0]55 433488 #