Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!orc!inews!iwarp.intel.com!ogicse!pdxgate!parsely!percy!qiclab!techbook!fzsitvay From: fzsitvay@techbook.com (Frank Zsitvay) Newsgroups: comp.os.cpm Subject: Re: 8 meg limit Message-ID: <1991Jan25.212329.27337@techbook.com> Date: 25 Jan 91 21:23:29 GMT References: <1991Jan23.223619.49@skyler.mavd.honeywell.com> <4402@mentor.cc.purdue.edu> Organization: TECHbooks of Beaverton Oregon - Public Access Unix Lines: 20 In article <4402@mentor.cc.purdue.edu> wilker@descartes.math.purdue.edu (Clarence Wilkerson) writes: >It seems to me like RLB's reply is a good explanation of why >the maximum size of file would be 8 megs, if we can access >sectors of the file by a 16 bit integer. Why does it dictate >the max. logical size of the disk, however? >Clarence well, it's like this - that same 16 bit integer that is used to address sectors in a file is also used to address blocks in a disk. therefore, the maximum available blocks on a disk is 65536, or 8192K bytes total. to access larger disks you would need a larger block pointer, something on the order of 24 bits or 32 bits. however, there is too much overhead associated with maintaining two pointers, and large ones at that, in an 8 bit system. it is just easier to accept the 16 bit pointers and work with them. -- fzsitvay@techbook.COM - but don't quote me on that.... American Oil Company motto - Bend over, We'll pump!!!