IV.	DECmate ROM sets

Modified from section IV of dminfo.faq.txt vy VRS.

Each DECmate system comes with a characteristic ROM set.  The DECmate I 
has a soldered chip set and is apparently only one revision in all viable 
machines.  Since the ROM is quite small, and additionally there is no 
slushware add-on capability, there is little built-in support routines 
for much beyond the built-in terminal emulator, etc.

DECmate II systems come with various ROM versions.  The version will be 
reported by running certain software systems, including WPS, etc.  Known 
versions include:

i.	31Z (3732)  This is the prerelease version found only in very old 
motherboards.  Unless the boards themselves are severely upgraded, the 
graphics option is not possible to be added.  The tell-tale sign of 
graphics compatibility is a two-prong connector under the board where the 
graphics board would mount.  (It's used to connect to a similar connector 
on the graphics board itself.)  The ROM set should be stamped with 358E2,
259E2, and 360E2.

Assuming the board is old, upgrading the ROM set will allow all other 
options to work.  31Z specifically cannot support the hard disk 
hardware!  Supposedly, DEC promised to provide a free upgrade to any 
system containing a board this old, yet many have shown up recently, etc.

ii.	18K (2213)  This is a prototype version used to develop hard disk 
capable machines that were likely never sold while machines equipped with 
31Z were being sold.  It is barely capable of supporting all options, 
although the board it may be placed in could be inadequate hardware!

iii.	19H (2310)  This version is quite common, but has self-test bugs 
that fail to find certain known hardware conditions that should be 
caught, such as pressing a key during self-test, etc.  The ROM set should
be stamped with 390E2, 391E2, and 392E2.

iv.	19N (2316)  This is the final ROM version and has no known bugs.

DECmate III systems apparently come in one of two ROM versions:

i.	32H (4010)  This is the usual DECmate III ROM and has no known
problems.  It should be stamped with 330H4.

ii.	32I (4011)  This is an obscure version recently discovered.  It 
is not currently known what the difference (if any) there is between this 
and the previous version.

DECmate III+ systems generally have only one version of ROM: 48E (6005).  
Presumably there are no known bugs, etc.

All of the ROM's can be obtained to allow upgrade of any DECmate system 
except DECmate I.  They are all socketed chips.  DECmate II systems use 
three 2716 chips while DECmate III series systems use a single 2764 
chip.  Additionally, both systems use a single 2764 as a character 
generator ROM.  DECmate III systems use a slightly different character 
set which at least causes the vertical bar character to appear unbroken 
while DECmate II systems break the bar as in most IBM-PC systems, etc.  
While there may be other differences, the two chips have been 
successfully interchanged with no ill effects, etc.