Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!zephyr.ens.tek.com!tektronix!percy!nosun!techbook!fzsitvay From: fzsitvay@techbook.com (Frank Zsitvay) Newsgroups: comp.os.cpm Subject: Re: 8 meg limit Message-ID: <1991Jan25.012406.13752@techbook.com> Date: 25 Jan 91 01:24:06 GMT References: <4314@mentor.cc.purdue.edu> Organization: TECHbooks of Beaverton Oregon - Public Access Unix Lines: 30 In article <4314@mentor.cc.purdue.edu> wilker@gauss.math.purdue.edu.UUCP (Clarence Wilkerson) writes: >I believe that the 8meg limit is set in the coding of >the BDOS, and inforced in the BIOS in the sense that >certain scratch ram in the BIOS data area has a preset >size. > I think several replacement BDOS clones, e.g. >DOSPLUS, offer larger maximum logical disk size. > There would be some perfomance penalties for >using larger sizes, namely more directory entries >to check or larger logical block sizes. >Clarence Wilkerson well, not really. it is limited by the directory structure that is at the heart of all cp/m disk operations. cp/m only allows for a maximum of 65536 128 byte blocks. that is the maximum size of a file, or a whole disk. there is a built in mechanism in cp/m to allow the creation of partitions on a single physical disk. dosplus is essentially a different operating system than cp/m, and it allows a larger total disk space through a somewhat revamped directory structure. zcpr3 and zsystem do it through other techniques. -- fzsitvay@techbook.COM - but don't quote me on that.... American Oil Company motto - Bend over, We'll pump!!!