Xref: utzoo comp.sys.misc:1865 comp.os.misc:650 comp.misc:3894 comp.arch:6764
Path: utzoo!attcan!uunet!tektronix!tekcrl!terryl
From: terryl@tekcrl.CRL.TEK.COM
Newsgroups: comp.sys.misc,comp.os.misc,comp.misc,comp.arch
Subject: Re: The NeXT machine has been announced! (long)
Message-ID: <3181@tekcrl.CRL.TEK.COM>
Date: 19 Oct 88 16:39:13 GMT
References: <360@elan.UUCP> <2070@cloud9.UUCP> <528@fabscal.UUCP> <1152@mmm.UUCP> <5826@killer.DALLAS.TX.US> <3542@phri.UUCP> <34946@clyde.ATT.COM>
Reply-To: terryl@tekcrl.CRL.TEK.COM
Organization: Tektronix, Inc., Beaverton,  OR.
Lines: 37

In article <34946@clyde.ATT.COM> wtr@moss.UUCP (Bill Rankin) writes:
>assumption: mach is somewhat similar to unix in it's use of disk
>swapping and paging.

     Bad assumption. MACH does not use the standard 4.2/4.3 method
of swapping/paging; MACH pages directly to a mounted file system.
It allocates inodes on the fly and then writes the pages out as part
of a regular file (but does not mark the inode as a regular file; it's
marked as an unknown type, in case the system crashes and fsck can easily
detect these unreferenced files and remove them as unneeded...). As a
side effect of this method of paging, one no longer needs a separate
partition for paging. One can make the whole disk one big hairy parti-
tion....

>i really don't think it's a good idea to un-mount (or the mach
>equivolent) the one and only filesystem.  remember, this is not
>mush-dos.  we just (probably) can't pop the OD out any old time we
>want to and plug in the new one.  nor can we eat up all the memory
>with a big fat juicey ram-disk without crashing the system.
>(remember we need program *and* swap space)
>
>i wellcome pointers on mach internals, etc... any mach gurus 
>reading?

     Well, since MACH is binary compatible with 4.3 BSD, the MACH
equivalent is unmount. But you're right about mounting/unmounting
the one and only file system. If the floptical (love that word!! (-:)
drive is the only drive, you can't easily swap disks like the Mac...


Boy
Do
I
Hate
Inews
!!!!
!!!!