68010 in the model 6000

[kb2syd]

Found this note:

	  MC68010 PROCESSOR SUPPORT FOR THE TANDY 16B/6000
	      XENIX/68000  Version 3.2(42a)  9 Nov 1987


    The kernel in this directory will allow owners of Tandy Model 16A,
16B,  and  Tandy  6000  systems  to  use  an MC68010 microprocessor of
identical speed in their CPU board in place of the standard 68000.

    The kernel changes to allow this were confined to one area.   They
have  been  heavily  used  on  the  systems  used  by the XENIX System
Programmers with no  problems.   The  68010  is  completely  backwards
compatible.  There are no application software changes required to run 
on a 68010.

    At this time, however, this version of /xenix  IS  NOT  officially
supported  or  approved  of  by Tandy Corporation or Radio Shack.  The
contents of this directory are provided "as is", witout  any  warranty
of  any  kind.   It  is  entirely  the  responsibility  of the user to
determine whether these files should be used with the  users'  system.
The  user  shall  make any adjustments or corrections necessary to use
these materials.  There is no commitment of any kind to provide  these
materials in a supported or unsupported form in the future.

    When reporting problems with your system, make  sure  the  problem
persists  when  running  with  the  standard  release of the operating
system.  (Yes, you have to put the 68000 back in to run  the  standard
release)

    Also, if you take your machine in for repair, BE SURE you  replace
the  68010 with the standard 68000, or the repair folk may think it is
bad and replace it with a 68000 (their diagnostics will not run  on  a
68010, sorry).

    This kernel was benchmarked against the regular kernel, and  while
there  were  improvments  in  several  areas, they were slight.  It is
doubtful that any significant performance improvement will be noticed.

    For a list of the differences between the 68010 microprocessor and
the  68000  consult  the  M68000 PROGRAMMER'S REFERENCE MANUAL, fourth
edition.

 

[Satyr Icon]

The 68010 had several major improvements over the '00 from an OS kernel implementor's perspective. Quoting Wikipedia:

The 68010 was pin-compatible with the 68000, but was not 100% software compatible. Some of the differences were:

• The MOVE from SR instruction is now privileged (it may only be executed in supervisor mode). This means that the 68010 meets Popek and Goldberg virtualization requirements. Because the 68000 offers an unprivileged MOVE from SR, it does not meet them.
• The MOVE from CCR instruction was added to partially compensate for the removal of the user-mode MOVE from SR.
• It can recover from bus faults, allowing it to implement virtual memory.

[...]

• It introduced a 22-bit Vector Base Register (VBR) that holds A[32:10] of the 1 KB-aligned base address for the exception vector table. The 68000 vector table was always based at address zero.

All of this sounds like OS catnip to me (well, not MOVE from CCR per se). I do wonder why virtualization didn't take off much sooner. If I remember correctly the x86 didn't satisfy Popek & Goldberg for several more processor generations and even then it was slow to arrive. Perhaps unfairly, I don't regard the 80386's "virtual 8086 mode" as real virtualization.

Anyway, a XENIX (or FUZIX ) that took advantage of the above features would be much sweeter system.

 

[pski]

From this note, it is highly unlikely that virtual memory was included in this release.

 

[P.H]

Hello Pete,
You had to send me photos of the CPU card 68000 8MHz.
* I will probably make a copy of that map. But I would like to know if there are wire correction on this map. I found his plan with a crystal of 48MHz
* Ian sent me a 68000 6MHz CPU card in 8MHz format with a 24MHz crystal. There are wired corrections on his card. They look identical but the 8MHz card has a U45 PAL in addition on the 8MHz card, near the crystal.
Do you happen to have .jed files from PALs? Tandy gives the equations of his PALs to me a copy of the PALs of a card is safer.
The CPU of the CPU68000 cards are 4 layers

Bonjour Pete,
Tu devais m'envoyer des photos de la carte CPU 68000 8MHz.
Je vais surement faire une copie de cette carte. Mais je voudrais savoir si il y a des correction par fils sur cette carte. J'ai trouvé son plan avec un cristal de 48MHz
Ian m'a envoyé une carte CPU 68000 6MHz au format de la 8MHz avec un cristal de 24 MHz. Il y a des corrections filaires sur sa carte. Elles sembles identiques mais la carte 8MHz a une PAL U45 en plus sur la carte 8MHz, près du cristal.
As-tu par hasard les fichiers .jed des PALs? Tandy donne les équations de ses PALs m'ait une copie des PALs d'une carte est plus sûr.
Le PCB des cartes CPU68000 sont des 4 couches
A+
Pascal