On Mar 13 2005, 20:00, Nico de Jong wrote:
> 55 listmembers have answered.
I was going to send a reply, but it got a bit long, and the gremlins
ate it while I left it lying around to be edited. +1 to the "50-54"
category.
--
Pete Peter Turnbull
Network Manager
University of York
On Mar 17 2005, 16:04, Randy McLaughlin wrote:
> There is confusion over pin 2 use at least in my head. The first use
was
> with the SA800 interface for reduced write current. Today on the 34
pin
> connector that is what it is now used for even for 3.5" drives.
> Traditionally the write current line was used completely differently
from
> how it is used today. Traditionally it changed according to where on
the
> disk the data is being written, for today's drives it is for the
entire
> media.
Yes, that's right.
> That is a side issue to my question about 765 TG43 controls.
>
> On a real 765 it generates the reduced write signal and outputs it on
the
> same controller pin as the direction signal.
>
> Today the 765 is emulated via VHDL code and I am curious as to
whether the
> TG43 logic was kept. I can and will experiment on my systems but I
would
> like to know if others are familiar with the issue.
>
> Obviously all PC's that use a real 765/8272 does generate the signal
and
> does bring it out to the 34 pin connector, it just happened to be
hidden on
> pin 18. I question if it is still there?
Well, I looked at the data sheet for the WD37C65, which used to be
fairly common, and the answer is "sort of". Pin 39 is the one that
you'd be interested in. It's an output labelled "/RWC,/RPM" and when
it's low, and the controller is in Base Mode, it says it causes a
reduced write current when bit density is increased towards the inner
tracks, being active when track > 28 (I think that refers to 40-track
drives, which would be 56 on an 80-track drive). This is very similar
to to the TG43 signal, except for being relative to a different track,
but it's not on the same pin as /DIRECTION (Pin 31). I can't help
wondering if "28" is a misprint for "23" or something like that, but I
checked two separate printings of the data sheet and both said "28".
It also says this function changes when in AT/EISA mode (it then
becomes completely under program control, and appears to be intended to
be used to set the density and/or speed for the whole disk) :-(
However, if you have control over the FDC rather than letting the BIOS
or DOS do it for you, you could make it do what you wanted.
I also looked at the Intel 82078 FDC, which is a successor to the 8272,
in either a 64-pin QFP package or a 44-pin PLCC, either 5V or 3.3V,.
and it was an antecedent of many of the multi-I/O chips. Unfortunately
it doesn't give enough detail.
Lastly, I looked at the NatSemi DP8473. It has /DIRECTION on pin 4
(PLCC version), and /LC (low current) on pin 51. Pin 51 just goes high
for HD media and low for SD/DD media (actually it goes low when 250kbps
or 300kbps data rates are set, instead of 500kbps). So it doesn't look
like that does what you'd want, either.
--
Pete Peter Turnbull
Network Manager
University of York
> I do not own a variac, so I will need to get one of these to
> properly reform the TU56 capacitors. I see several different
> varietieson eBay. What would I need exactly?
>
For re-forming the cap'sin my unit, my plan is to (hopefully this weekend), disconnect the screw terminals and use a programmable power supply [DC] applied direcly to the terminals. Current will be limited and the voltage slowly increased. If I can get the lab computer working, then it will be a nice slow smooth increase over a 12-24hr period. If I resort to adjusting the supplies manually I will end up making larger steps and watching the current..not as clean but still better than a full "bang".
>Subject: Used IBM equipment in Green Bay
>Date: Thu, 17 Mar 2005 16:43:34 -0500
>From: "Justin Nemeth" <Jnemeth at EPLUS.com>
>To: <jfoust at threedee.com>
>
>John,
>I have a customer in Green Bay looking to get sell, scrap, get rid of the following equipment
I think they are fairly large boxes..
>
>Let me know whether or not your interested
>
>Thanks
>
>Regards,
>Justin Nemeth
>ePlus Group, Inc. (Midwest)
>Ph:630-790-2203
>
>
>Equipment:
>IBM 3745-210 Communication Controller --
> with the following features:
> (8) 1561 - Channel Adapters
> (2) 4720 - Low Speed Scanner
> (1) 4770 - Token-Ring Adapter Type 2
> (1) 4900 - Lic Unit
> (6) 4911 - Lic Type 1
> (5) 4931 - Lic Type 3
> (1) 7100 - Storage Incement 4 MB
> (2) 9720 - Basic Low speed Scanner
> (1) 9763 - Tsst Board With Tra Option
> (8) 9911 - Basic Lic Type 1
>
> Approximate Date Available - April 2005
>
> (2) IBM 9393-T82 Virtual Array Units
> (1) 9393-X82 Virtual Array Unit
>
>
>From: "Randy McLaughlin" <cctalk at randy482.com>
>
>On the Nec 765 (Intel 8272) the direction pin is also use for reduced write
>current (TG43).
>
>When the step line pulses the direction pin controls the direction. All
>other times it is high if the track counter is 43 or less, low if the track
>counter is greater than 43.
>
>The current disk controllers are based on the 765.
>
>Does anyone know if the direction pin does the same on the newer clone
>chips? I have started looking at the datasheets but so far I have not found
>any reference to that function on "modern" parts.
>
>If it's true then the 34 to 50 pin cable I use (and others) can be made to
>include TG43 without using an adapter like FDADAP.
>
>It may turn out some do and some don't but since everyone is basically using
>the same licensed core I would expect all newer chips to act the same. The
>question is was TG43 support kept from the original 765?
>
>
>Randy
>www.s100-manuals.com
Hi Randy
See web page:
http://www.dbit.com/fdadap.html
You'll note that it mentions that a normal PC does not
supply the TG43 signal. Their adapter includes what looks like
a uP to keep track of the current track to generate this
signal for writing to 8 inch disk.
If you were doing software to write 8 inch disk, I would guess that
you could double up this function on the step direction wire.
There is otherwise no signal to do this for you.
Don Maslin's connection was primarily to be used for reading
9 inch disk. It may also be assuming that the drive has a built
in track 43 sensor.
I think this is were the confusion over pin 2 comes in. This
is usually uses as a speed control on PC's but historically
it was a write current control.
Dwight
All:
I'm longing to add a hard disk system to the Altair emulator. I came across a 3-part series in BYTE (March - May 1983) for a host-computer adapter manufactured by ASC Associates connected to a XEBEC-S1410 based 10mb SASI Winchester drive.
In part 3 of the article, BYTE printes the complete CBIOS, but the article stops in the middle of the code around page 400 of the issue. I have a nearly-complete series of BYTEs and I haven't found a reference to the code in any subsequent issue.
So, here's the question...does anyone have a copy of the complete CBIOS from the article *or* have a CBIOS for another XEBEC-based setup?
Any help is appreciated. Thanks.
Rich
--------------------------------------------------------------------------------
Hi,
of late we have had been trying to develop a software for a London based music company which uses Jukeboxes that works on CC-TALK BACTA Protocol.We have tried our level best to find the Message Format which the cctalk understands both for serial and Parallel port interfaces , but unfortunately we couldnt find one.There were documents that made allusive expalination about the message formats but nothing in detail as to what all means in the colection of bytes that constitue a port communication. Can you on behalf of CCtalk respond back with a manual that addresses the same.Apart from that may I be obliged by one further level by you with any sample software program in any language that deals with CCTalk Messsge handling logic.
I am eagerly looking forward for a positive response at your earliest convenience.
Regards
Shaneit
Cygnus Software Pvt Ltd
568 Narayan Peth
4Th Floor Kesri Wada
Pune - 411030
--------------------------------------------------------------------------------
For those that are interested. I sent my age previously, and was guilty
of waiting too long.
Hardware experience: somewhat chronological
Some IBM EAM (machines) with the big patch boards
Control Data Corp 6600
PDP 11/10
PDP-12
PDP-8
IBM 360
CDC 7200
IBM 370
PDP 11/34
PDP 11/44
PDP 11/60
Data General Nova 3
DG Nova 4
Some S100 bus stuff (Imsai, Altair, etc)
Some STD bus stuff
DEC LSI-11
DEC LSI-11/2
DEC LSI-11/23
Rockwell 6502
Zilog Z80
Intel 8080/8085
Zilog Z8
Motorola 68008
IBM PC
IBM PC/XT
DEC LSI-11/73
IBM PC/AT
Basic Stamp
486, pentium, etc.
Programming experience (not just using equipment)
Assemblers:
IBM 360 and 370
DEC PDP 8 and 12
DEC PDP-11
CDC 6600/7200 (Cyber 7200)
Nova 3 and 4
6502
8080/8085
Z8
Z80
68000
Basic Stamp
Higher level languages: (some not so proficient and some pretty
forgotten by now)
Cobol
Fortran
Basic, Visual Basic
Dibol
Pascal
Turbo C
C, C+, Visual C
Java
Perl
Joe Heck
>From: "Guy Sotomayor" <ggs at shiresoft.com>
>
>On Thu, 2005-03-17 at 11:00 -0500, Ashley Carder wrote:
>> I do not own a variac, so I will need to get one of these to
>> properly reform the TU56 capacitors. I see several different varieties
>> on eBay. What would I need exactly?
>
>If I'm not mistaken the whole reforming capacitors discussion was for
>electrolitic capacitors (ie DC). The motor run capacitors are AC. I'm
>not sure the reforming process would be the same (or if it is even
>possible).
>
>Anyone want to comment?
>--
>
>TTFN - Guy
>
>
Hi
AC electrolytics can be similarly reformed, using a
current limited AC source. Many run capacitors are
electrolytic but may also be large oil and paper.
Most anything over 10 mf is probably an AC electrolytic.
Dwight
>From: "John Allain" <allain at panix.com>
>
>> 20amps, wow. Someone give me this for christmas!
>
>
>I now have Two nice machines (Tek scope, VT100) that blow
>fuses and have been dancing aound the issue to get one for a
>few weeks now. I'm not really an electronics guy but I've been
>led to believe that a variac is the single best thing to get to help
>remedy fuse blows. Any strong yes or no votes towards this
>decision?
>
>John A.
>
Hi
If you've hit a capacitor hard enough to blow a fuse, it
is not likely to recover through reforming. Reforming
must be done before applying full voltage.
Most issues of blowing fuses can be located by isolation
and use of an ohm meter.
Dwight
