robin@medstar.UUCP (Robin Cutshaw) (06/03/85)
This article refers to Xenix (286 3.0)...
A major limitation of Xenix on the PC/AT is the 1 Megabyte file size
limit. Only effective uid 0 may write files larger than this and the
function ulimit(cmd,newlimit) must be called with cmd=UL_SFILLIM from
<sys/ulimit.h> and newlimit is a long representing 512 byte blocks. The
associated variable is u.u_limit (S3 u_limit was set to 5000 blocks).
This is a major limitation for utilizing large databases. IBM says
that this should be fixed soon.
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Robin Cutshaw
uucp: ...!{akgua,gatech}!medstar!robinguy@sun.uucp (Guy Harris) (06/06/85)
> A major limitation of Xenix on the PC/AT is the 1 Megabyte file size > limit. "ulimit" is a hack, and a poor one at that. The code is lousy - first, because it's done in the kernel, rather than by "init" with the limit specified in a file, so it's not an easily-tunable parameter, and second, because the value is NOT a define constant, but a magic number! It does NOT provide a way to restrict usage of the disk, because it merely restricts the size of an individual file, not the total disk block consumption of a user or process. It does, however, make life difficult for programs that need a file of that size. The correct way to restrict disk usage is with disk quotas. You can get UNIX systems with disk quotas; however, you can't get them from AT&T.... Furthermore, a ulimit other than 0x7fffffff for a single-user workstation is stupid. > This is a major limitation for utilizing large databases. IBM says > that this should be fixed soon. Let's hope AT&T realizes the same thing and fixes it in System V Release n, for some value of n. Until that time, let's hope all the resellers of S5 realize the same thing and fix it. Guy Harris