xenix for tandy 16

[Robert Dinse]

In article <1991May15.010705.16412 at sbcs.sunysb.edu>, jallen at csserv2.ic.sunysb.edu (Joseph Allen) writes:
> 	  can someone tell me hardware requirements for various versions
> 	  of xenix (disk space, memory space, model, etc)

     There are various versions, anything newer than 1.03.05 requires a
PAL chip upgrade to the CPU. I don't know any easy way of finding out if
you have it or not other than trying to boot 3.00.00 or later off of floppy.

     All versions Tandy sold will fit on a 15 meg hard disk. It's a question
of how much room you need for other applications.

> 	- Does the version of xenix for these machines have:
> 		C compiler & libraries

     The development system was a seperate item that had to be purchased
seperately. The C compiler and libraries come with the development package.

> 		Virtual memory

     No, the memory management hardware on the Tandy 6000 has only two offset
and limit registers, the MC68000 doesn't support virtual memory, and even
though they supplied a kernal for MC68010 in their 3.02.00 release, they did
not take advantage of the virtual memory capability of the MC68010.

> 		Any quirks I should know of?

     Lots.. Prior to 3.02.00 compilers were limited to 7 character symbols.
Without an MMU upgrade you are limited to 1 meg of RAM (pretty confining on
a machine without virtual memory). The stack, BSS, and Data segments share
a common segmentation register and the stack is not dynamic, if it grows
farther than the amount of space specified at compile time it will overwrite
the BSS and Data segments causing programs to execute erratically before it
gets far enough to cause a segmentation violation and core dump.

     Even the 3.02.00 development system compiler does not support void data
types. GCC fixes some of these evils but it requires a lot of memory. I have
4-megs on this machine and that is marginal for GCC.

     3.02.00 added auto-boot capability and the ability to format floppies
while in Xenix instead of having to boot diskutil. But 3.02.00's init dies
occasionally. The tty drivers for the 3-port boards on every version of Xenix
I've used are flakey and lock-up under certain conditions.

     There are compatability problems between the disk controllers and
certain drives. These do not seem to be consistant from one machine to the
next.

     For what it's worth, I replaced the WD1010 with a WD2010 on my system
and it was a worthwhile upgrade. For reasons I don't fully understand the
WD2010 seems to work with some drives that the WD1010 didn't like.