[TUHS] Unix install & "standalone" package

Norman Wilson norman at oclsc.org
Tue Sep 5 00:44:21 AEST 2023

I don't remember any special many-programs-in-one binary
like busybox in any Unix from the days when Unix was simple
enough for me to understand.  That covers the entire lifetime
of the Research systems, but also System V and the BSDs and
their sundry offspring up into at least the 1990s.

I'm pretty sure OpenBSD at least still has nothing like
busybox.  The nearest thing was to make sure certain programs
were linked statically (or existed in alternate statically-
linked versions) so they would work before shared libraries
were available.  (It seems to be common wisdom that `sbin'
means `system bin' these days, but I remember once, long ago,
being told it stood for `static bin'.)

Perhaps the question to ask is why such a magic program is
needed at all.  Is it just because programs like the shell
have become so large and unwieldy that they won't fit in
a small environment suitable for loading into an initramfs?

Older UNIXes, even on the VAX, didn't use an initramfs.
the boot code had just enough understanding of devices and
file systems to load the kernel and to point it at the
real root file system.  The VAX hardware designers had
a clever scheme on many (but, strangely, not all) VAX
variants by which the hardware had several little boot
ROMs, each containing a bare-bones read-only device
driver for a particular device along with a few
instructions to read the first sector into memory
and start it, with pointers to the boot-rom driver
and device ID in specified registers.  That was enough
to support a device-independent Unix boot block that
could read unix (or another file name typed on the
console) from the root of the file system at the start
of the disk.  I know it was because I wrote such a
boot block, though I don't know whether anyone else
did.  (Other systems, I think, just used it to load
/boot, a larger and more-capable program.)

Maybe it was just that the boot environment was simpler
in older systems, without the need to load kernel modules
or support multiple locations and means of access for
the root?

Norman Wilson
Toronto ON

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