[rescue] Help with SunFire V240 Server

[Carl R. Friend]

    On Sun, 7 Apr 2013, Sandwich Maker wrote:

> the general consensus has always been, if the sun takes an sca hd
> it'll take -any- sca hd.  my experience isn't vast [half vast?], but
> i've never been disappointed.  my worst problem was finding an
> acceptable geometry for format.

    This has been my experience as well; modern kit will take pretty
much whatver drive you throw at it.  Even "format" has loosened up
quite a bit since the demise of C/H/S addressing in favour of LBA
addressing and tends to do a good job at identifying disks based
on an inquiry.

    The only place I've run into problems has been in very old gear
(late '80s and early '90s) that use signed 32-bit arithmetic in
dealing with block numbers.  Some of those will get confused if you
throw something huge at them.  Too, in some cases, modern disks are
bigger than the address can allow for and those can do strange things
if you wrap the address (VAXen and boot-disks >1G seem to come to
mind).  Anything newer than about 2003 really ought to be handle most
anything that'll come down the 'pike in the next several years with
the possible exception of some under-engineered (or intentionally
crippled) IDE kit.

    On signed arithmetic for logical-block addressing -- WHY?  The
cynic in me leans towards laziness or lack of attention to detail.
Surely a negative block would lead to either a seek-to-spindle event
or an unload (depending on where cylinder 0 is).  Why not use the
whole width of the word to express an absolute offset and be done
with?  You get twice as many blocks by not wasting the sign bit.

    Cheers!

+------------------------------------------------+---------------------+
| Carl Richard Friend (UNIX Sysadmin)            | West Boylston       |
| Minicomputer Collector / Enthusiast            | Massachusetts, USA  |
| mailto:crfriend at rcn.com                        +---------------------+
| http://users.rcn.com/crfriend/museum           | ICBM: 42:22N 71:47W |
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