jmm@skivs.UUCP (Joel M. Miller) (10/05/90)
Has anyone noticed that available disk space is about 5,000K less when logged in as a normal user (eg Guest) than when logged in as root? Recall that I have set up my 80MB disk with "/" and "/users" on the same partition. That is, when I log in as root, "df /dev/c5d0s0" says that I have about 7,000K available, while as jmm or Guest, 2,000K. I thought that the only difference between root and normal user logins was permissions. (A bit of self-defeating advice: don't even *think* of running A/UX off an 80 MB disk! Self-defeating, because as soon as I scrape up money for a big disk, my 80 will be for sale!) -- Joel M Miller Internet: jmm@skivs.ski.org Smith-Kettlewell Institute Usenet: fernwood!skivs!jmm 2232 Webster St Bitnet: jmm%skivs.ski.org@fernwood.mpk.ca.us San Francisco, CA 94115 Voice: 415/561-1703 Fax: 415/561-1610
rmtodd@uokmax.ecn.uoknor.edu (Richard Michael Todd) (10/06/90)
jmm@skivs.UUCP (Joel M. Miller) writes: >Has anyone noticed that available disk space is about 5,000K less >when logged in as a normal user (eg Guest) than when logged in as root? >Recall that I have set up my 80MB disk with "/" and "/users" on the >same partition. That is, when I log in as root, "df /dev/c5d0s0" >says that I have about 7,000K available, while as jmm or Guest, 2,000K. >I thought that the only difference between root and normal user logins >was permissions. You obviously are new to machines with BSD-style filesystems. On any Unix machine with BSD-style FS (aka "Fast File System" or "UFS"), by default 10% of the disk space is reserved for root only. The reason is that the allocation policies BSD uses to allocate disk space "optimally" (i.e. not fragmenting your file all over the disk, requiring mucho seeks), don't work well when the filesystem gets more than 90% full. Now, this policy works fairly well on big university-owned machines (where BSD originated) where they've got lots of big disks hanging off their Vaxen, but for those of us with our dinky little 80M Quantums, we need that extra disk space. Fortunately, the default can be changed with the "tunefs" command; check out the man page on it. You can set the "free space reserve" percentage down to 0. >(A bit of self-defeating advice: don't even *think* of running A/UX off >an 80 MB disk! Self-defeating, because as soon as I scrape up money >for a big disk, my 80 will be for sale!) I agree, the 80M is a bit cramped, especially if you want to run netnews on it. (I did that under 1.1, with a very small set of newsgroups, but it wasn't pretty, and I don't think I could have gotten away with it under 2.0). Me, I added an external 300M instead of getting rid of my internal 80M. I'd rephrase your advice to be "don't even think of running A/UX with only 80M total disk on your system. Especially if you like X Window :-). -- Richard Todd rmtodd@chinet.chi.il.us or rmtodd@uokmax.ecn.uoknor.edu "MSDOS is a Neanderthal operating system" - Henry Spencer