Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!columbia!rutgers!sri-spam!sri-unix!ctnews!pyramid!uccba!hal!ncoast!allbery From: allbery@ncoast.UUCP (Brandon Allbery) Newsgroups: comp.unix.wizards Subject: Size of SysV "block" Message-ID: <2744@ncoast.UUCP> Date: Tue, 30-Jun-87 20:30:34 EDT Article-I.D.: ncoast.2744 Posted: Tue Jun 30 20:30:34 1987 Date-Received: Thu, 2-Jul-87 02:45:00 EDT References: <218@astra.necisa.oz> Reply-To: allbery@ncoast.UUCP (Brandon Allbery) Followup-To: comp.unix.wizards Distribution: world Organization: Cleveland Public Access UN*X, Cleveland, Oh Lines: 33 As quoted from <218@astra.necisa.oz> by dave@astra.necisa.oz (Dave Horsfall): +--------------- | Can anyone tell me in an unambiguous manner just how many bytes | are in the following System V (2.?) "blocks"? Make any assumptions | uou like, if it makes a difference. I have yet to see a clear | reference on this matter. (BSD people stop laughing, I'll bet you're | not much better off!) +--------------- There is no single "block" size. Instead, there are "tape blocks" -- usually 512 bytes for historical reasons (and thereby compatibility) and "disk blocks" (which used to be 512 bytes but on most modern systems are 1024). If you have an improperly ported System V (or a clone System V that was never within 10 miles of AT&T since it was V7 compatible), you may have 512-byte blocks no matter what, or some/all of the programs may not have been changed to reflect the new block size. WOrse, System V can handle both kinds of filesystems, so you may have a partition with 512-byte blocks and one with 1024-byte blocks.... In general, tape-oriented utilities (tar, dd, cpio) use tape blocks (512 bytes) and disk utilities (including stdio) use 1024-byte disk blocks even on 512-byte block file systems. (Low-level utilities like mkfs and fsck/fsdb will use the actual block size of the file system.) ++Brandon -- ---- Moderator for comp.sources.misc and comp.binaries.ibm.pc ---- Brandon S. Allbery !cbosgd!ncoast!allbery aXcess Company {ames,mit-eddie,harvard,talcott}!necntc!ncoast!allbery 6615 Center St. #A1-105 {well,sun,pyramid,ihnp4}!hoptoad!ncoast!allbery Mentor, OH 44060-4101 necntc!ncoast!allbery@harvard.HARVARD.EDU (Internet) +01 216 974 9210 ncoast!allbery@CWRU.EDU (CSnet) Brandon Allbery on 157/504 (Fidonet/Matrix/whatever)