Super Block Position

Super Block Position

Post by Paul » Wed, 02 May 2001 17:30:07

From the AST textbook, the superblock is right behind bootblock, after the first 1024 bytes, right?
But when I do this:
1. zero out the floppy disk
2. partition it into fd0a and fd0c, and take a snapshot of the entire disk  (using xxd)
3. mkfs /dev/fd0a, and take another snapshot of the disk  (using xxd)
    this step should , in theory, write the super block right? and maybe some other info.

but when I compare the difference between the two image, the difference occurs way after the 1024 byte. In fact, the first difference occurs at:
< 0002800: 0000 0000 0000 0000 0000 0000 0000 0000  ................
< 0002810: 0000 0000 0000 0000 0000 0000 0000 0000  ................

Quote:> 0002800: d000 0000 0100 0100 1100 0000 001c 0404  ................
> 0002810: 6824 0000 5b02 0000 0000 0000 0000 0000  h$..[...........

This is weird..., or the textbook on page 456 is wrong?
Thanks for any input.

1. df can't read my (hard disk) super blocks

] I have MacMinix 1.5.10 and I installed it on my 40 meg drive, giving
] 950k to the ramdisk-based root filesystem and 32767 blocks (Q: is this max?)
] to the usr filesystem. (To wbb: I _actually_ got it installed! TNX!)
] Otherwise, things seem to be working fine, on Mac System Software vers. 6.0.5;
] it dies an unnaturally horrible death under system 7.0 w/ tune up.
 From what I've heard, Minix won't work under System 7 (32-bit
cleanliness or something).  I've personally had it work under System
7.1 without 32-bit addressing or VM enabled; 32-bit addressing might
work, but VM breaks it for some reason.  BTW, if you want to upgrade
(cheap) to System 7.1, mail me.  I won't give it to you (that'd be
illegal), but I'll let you know a cheap and legal way to get it (the
way I got it).

] Another question I have is can the Communications Toolbox be a TTY?
Not that I know, since Minix hasn't even been rewritten for System 7
and that's pretty much a "7 thing".  I don't see why someone'd want it
anyway -- maybe to access a serial port board?  Why not just write a
hardware driver for the board and run Minix alone (i.e. without the
Finder running) on your machine.  IMHO this is a better way to go --
some people I met a while back wanted to do this with the whole OS but
it'd be hard because of hardware differences between models.  But for
an expansion card...

] Thanks in advance
No problem -- I love rambling. :-)  BTW, what kind of Mac do other
people (such as yourself) use for running Minix?  I'm using a IIci 5/80
with no cache card right now and I only get 3125 dhrystones [no
benchmarking flames please!  I know it's not that accurate] with an
optimized dhrystone and an optimized kernel with nothing but dhrystone


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