From: jhwhit01@ulkyvx.louisville.edu
Newsgroups: comp.sys.ti
Subject: Re: NCTIS report
Date: 21 Jan 93 11:57:00 GMT
Organization: University of Louisville

In article <00966DA4.0EDB0FE0@GOMEZ.PHYS.VIRGINIA.EDU>, cohen@GOMEZ.phys.virginia.edu writes:
> In article <1993Jan19.035319.1@ulkyvx.louisville.edu>, jhwhit01@ulkyvx.louisville.edu writes:
>>Here is the most recent NCTIS report that I have seen.  I thought you might
>>find it of interest.  I have not edited it in any way.
>>  
>>Hardware standards decided-
>> 
>>     LEVEL C             LEVEL B PLUS: RS232, DOUBLE SIDED SINGLE DENSITY DISK
>>                         DRIVE AND CONTROLLER (ALL CONTROLLERS DO DSSD)
> 
> Note there is no level for a DS/DD (MYARC/CORCOMP/ATRONIC) disk controller
> upgrade.  I think this is just as well.  I always felt the TI-controller
> was the best of all, and that the DD of the other controllers did not
> really give that much except for a doubtful TI<-->IBM transfer and some
> increase in disk access (alas, along with a decrease in system reliability
> and compatibility)
> 
I think the MYARC DDCC (floppy controller) is probably the best of the lot.
Mine has always been reliable since I bought it in 1986.  From a reliability-
standpoint, the TI controller probably cannot be beat.  However, it has what I
consider a clunker of a hardware interface.  The Corcomp justs adds more and
more complications to the TI mix.  The CC card, depending on what version you
might use, can be quite unreliable.  The HFDC is basically a good hardware
design, but the chipset MYARC used has some bugs.  The bugs in the HFDC DSR
do not help matters.  The Percom card that I have is reliable, though I know
some were not.  The Percom is basically a clone of a TI card built as for a
box that attaches to the console via a ribbon cable.  I have both MYARC, the TI,
the Percom, and one of the CC units.  The HFDC sees the most use, because it
is fast and I have it on my Geneve where it has been reliable.  The MYARC DDCC
sees action the rest of the time.  It is reliable on both TI and Geneve systems.
The TI, Percom, and CC cards are used when I need to run more than 2 systems,
or when I need to check code for compatibility.  
 
One annoying "feature" of the HFDC is that it cannot read all disks made by the
other controllers.  Early versions of MDOS not meant for use with the HFDC and
predating the HFDC would write incompatible formats.  I have a stack of 720K
disks written with my DDCC(-80) that cannot be read by the HFDC.  By far the
worst offender is CC, which writes a single-density format that the HFDC can
not read properly.  The data structures for the DDCC(-80) and HFDC 720K are
one and the same, and the data structures for all single-density disks among
the controllers are the same.  However, as Barry Boone described and I have
confirmed, these HFDC-unreadable formats are because there are not enough gap
bytes after the disk index.  This causes problems with the HFDC data separator
circuit (which on several cards is not up to spec, but even when that is fixed,
does not solve the compatibility problems).
  
However, I am drifting from the topic -- though I guess you could say that if
Corcomp had followed the standards set down for formatting single density, I
would be able to read with the HFDC this disk I was given a couple weeks ago.
The Level C standards are minimal standards for that level.  Nowhere is a
specific brand of controller specified.  Because all controllers can handle
non-CC single density, that is what was specified.  These hardware levels
are meant to help software target their products to users.  Specifying levels
that support 360K (DSDD) or 720K (DSDD-80) disks would really narrow the
market at that level.  Most users have TI controllers, and those are what are
most often found second-hand.
 
>> 
>>     LEVEL D             LEVEL C PLUS: 128K OR GREATER CPU RAM BANKABLE IN AT
>> 
>>First project-
>> 
>>Write a universal DSR for memory access to all current extended memory cards
>>(Myarc/CorComp 128/256/512k, RAMBO, Geneve, RAVE, Etc...)
> 
> Why are the Founadtion and Morning star 128K cards not supported?
 
The Foundation and Morningstar cards fall under the category "Etc."  If any
person can provide information on how to use them (the Foundation can be
upgraded to work like a MYARC 128K or 512K, and the Morningstar can work like
RAMBO), there will be no problem with supporting them.  The purpose is not to
exclude anyone if it can be helped.
 
> 
Newsgroups: comp.sys.ti