On Apr 5 2005, 16:19, Phil Spanner wrote:
> Thought I wouold drop a note regarding the drives. Not only does BIOS
need to be configured (usually by type) but my drives seem to need 2
cables???
> One floppy drive cable should not enable the controller to talk to
the drives at all.
Well, up to a point. The 34-way cable carries the control signals,
such as the drive selects, head selects, step, write-enable, etc, and
status signals such as ready, track zero, etc. The 20-way cable
carries only the differential read and write data signals. Without
that, of course, the controller will never see data from the drive.
--
Pete Peter Turnbull
Network Manager
University of York
On Apr 5 2005, 17:10, Brad Parker wrote:
>
> I bought an RX01 8" drive and it has no drive electronics card on it.
>
> I have an RX11 M7846 controller (host adapter).
>
> I assume to make this work I need an electronics card on the RX01
drive
> itself. The drive has what looks like mounting holes for a PCB and I
> the RX11 is way too simple so I assume there is something which bolts
> onto the RX01 drive. And a ribbon cable between them. And a power
> supply :-)
Yes, but perhaps not quite in the form you might expect. As Henk
mentioned earlier, there are two boards in an RX01 or RX02, and they're
both quite big -- they sit one above the other and each spans across
two drives. Not at all like SA800-style drives, which normally have
one PCB on the top of each drive. The power supply is mounted behind
the drives on a substantial chassis, to part of which the two PCBs are
also mounted (the upper one is hinged at the left hand side to provide
access to the lower one).
Your host adapter is little more than a parallel interface; it talks
over a 40-way ribbon cable (but less than half the pins are used) to
one of the boards on the RX02 unit which has a state machine to execute
various commands, and that board in turn connects via another ribbon
cable to the lower board, which has the amplifiers and so forth on it.
The head cables plug into this lower board.
AFAIK the drive mechanisms for an RX01 and RX02 are the same; only the
boards differ.
--
Pete Peter Turnbull
Network Manager
University of York
On Tue, Apr 05, 2005 at 03:57:24PM -0500, cctalk-request at classiccmp.org wrote:
> Wait -- the Miniscribes are MFM, yes? You should be testing them with the WD
> controller, not the RLL controller.
No, they are RLL. 8438 are RLL variant of the 8425. They ran for years
with the 27X controller in my family's XT :)
> Also, since you're testing on a 386, go into the 386's BIOS and make sure that
> the 386 isn't trying to map something into the ROM address space that the
> controllers are trying to use (ie see if it's possible to relocate the 386's
> onboard IDE controller BIOS location, if it has one -- my Dell 316sx works like
> this, for example... can also relocate video ROM location too).
This is a 386 clone board without any onboard peripherals.
> If you exhaust all options, send me the MFM drive -- I have a 100% working
> WD1002 system set up right now with an ST-225 and could take a look at it for you.
I'll keep that in mind, thanks!
> Isn't that only a requirement of SCSI drives? I certainly don't have any
> terminators on my MFM/RLL drives...
These are terminating resistor packs which are located on the drive PCB,
not a terminator in the SCSI sense where it's plugged into the end of
the chain. Also, I believe SCSI terminators are composed of
transistors, not resistors.
--
Ryan Underwood, <nemesis at icequake.net>
>Subject: Re: rx01 w/o controller board
> From: Brad Parker <brad at heeltoe.com>
>
>"Eric Smith" wrote:
>>Brad wrote:
>>I bid on an RX01 on ebay, hoping it had a controller card. Naturally it's
>>> just the drive. [...] where can I get a controller card [...] Naturally
>>> I have an unibus rx01 controller card, so all I need is a controller card
>>> for this drive, right?
>>
>>I'm completely confused. You have a controller card? Or you don't? If
>
>Sorry. To much coffee and emulators today :-)
>
>I bought an RX01 8" drive and it has no drive electronics card on it.
>
>I have an RX11 M7846 controller (host adapter).
>
>I assume to make this work I need an electronics card on the RX01 drive
>itself. The drive has what looks like mounting holes for a PCB and I
>the RX11 is way too simple so I assume there is something which bolts
>onto the RX01 drive. And a ribbon cable between them. And a power
>supply :-)
>
>-brad
Brad did you buy a bare drive? If so you need the cab, power supply and
both logic cards. Yes in the RX01 dual drive there is a pair of cards
that are drive interface and processor. the RX11 is just an interface
to the processor.
Allison
>Subject: Re: rx01 w/o controller board
> From: "Jay West" <jwest at classiccmp.org>
> Date: Tue, 05 Apr 2005 16:17:48 -0500
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>Brad wrote....
>> I assume to make this work I need an electronics card on the RX01 drive
>> itself. The drive has what looks like mounting holes for a PCB and I
>> the RX11 is way too simple so I assume there is something which bolts
>> onto the RX01 drive. And a ribbon cable between them. And a power
>> supply :-)
>
>I have a problematic RX02 "internal" controller card, I was in a hurry to
>get the drive operational and just bought a new card for it. You're welcome
>to the old one (which obviously needs some repair), if it will help in your
>quest.
RX02 does not work with RX11, also the bords for rx02 and rx01 are "sets"
that I've found are not cross interchangeable.
If you building up an RX01 you need both drive internal boards and RX11
to be of the RX01 part group.
I know this as my RX02 started life as an RX01. Then I changed the drive
boards and use a RXV21 with it.
Which RX01 card do you need the Drive interface or the "processor" board?
Allison
>
>Subject: Re: rx01 w/o controller board
> From: "Eric Smith" <eric at brouhaha.com>
> Date: Tue, 05 Apr 2005 11:50:38 -0700 (PDT)
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>Brad wrote:
>I bid on an RX01 on ebay, hoping it had a controller card. Naturally it's
>> just the drive. [...] where can I get a controller card [...] Naturally
>> I have an unibus rx01 controller card, so all I need is a controller card
>> for this drive, right?
>
>I'm completely confused. You have a controller card? Or you don't? If
>you have one, surely you don't need one? Or are you saying that you need
>one for a different bus? Or is your drive missing the drive electronics,
>which is the real controller (vs. the Mxxxx "controllers", which are
>really just host adapters)?
>
>The "controllers" (host adapters) are:
>
> Unibus Qbus Omnibus
> ----------- ----------- ----------
>RX01 RX11 M7846 RXV11 M7946 RX8E M8357
>RX02 RX211 M8256 RXV21 M8029 RX28 M8357
Eric, Sound to me like he got a bare drive and no 54-xxxxx boards
and PS to make a complete rx01. Iv'e found the base mechanics are
common as people part out rx01/02s for the boards or PS.
Brad,
If you listening the real RX01 is heavy, two drives
in a rack width cab nearly 11" high, contining a
powersupply and two long cards that supply drive
interface (for both drives) and processor (nearly a
complete FDC in itself).
Allison
Hi,
Yes, for it's time (1976) the SC/MP had the logic that allowed it to share
the bus with other processors etc. The 8080 chip could also do this, but
this device required 3 separate power supplies and you needed three chips
to get the CPU working properly. The 6800 also offered similar multiprocessing
abilities and, like the SC/MP was a single chip system, but I'm not sure if it
came out before or after the SC/MP.
The SC/MP I (ISPA/500) was a PMOS device and required +5 and -7 volt power
rails. The SC/MP II (ISPA/600) was NMOS and required only +5 rail (same as the
6800), it also had three of it's CPU control lines inverted (as compared to the
SC/MP I) and though it could take 4 times the speed of the clock of the SC/MP I,
due to internal clocking it ran only twice as fast.
What made the SC/MP popular back in those days was the cost. It was about a
quarter of the cost of the 8080 and 6800 processors.
The SC/MP, like some other early processors, such as the 2650, had it's memory
divided into pages, and the Program Counter couldn't access the entire memory
unless some specific registers or jump/load instructions were used.
The simplicity of the SC/MP instruction set (only 46 instructions) is it's strength, yet
also a part of its weakness (ie, page memory, no dedicated stack, no compare
instructions, no rotate/shift left, cumbersome interrupt, etc).
Half the fun is getting the hardware all going, and the rest of the fun is to lock horns
with it's instruction set and do some fancy programming.
I'll take a few pics of the system (including my homebuilt 8085 system) and let you know
when they are on the web.
Finally, it's good to see some other old SC/MP dudes around and also others who like
to build and program their systems from scratch.
river
Well, let's try to give an answer.
The SWitch Register is what is says: *switch* register.
So you can read the switches from it, but writing to it is no use.
Don't shoot me if I am mistaken! From memory, the address is 777570.
- Henk, PA8PDP.
-----Original Message-----
From: cctalk-bounces at classiccmp.org
To: Classic computer list
Sent: 5-4-2005 21:33
Subject: PDP 11/45 Display register.
Hi,
A quick question raised by my ongoing work....
Is it possible to write directly to the "display register" - the one
accessed by one position of the data switch. I think it should be at
memory
location 777570, but I can't get data into it, either using deposit from
the
console, or moving data under program control.
Have I got a fault, or am I doing something wrong?
Thanks
Jim.
Please see our website the " Vintage Communication Pages" at
WWW.G1JBG.CO.UK
Hi,
Thought I wouold drop a note regarding the drives. Not only does BIOS need to be configured (usually by type) but my drives seem to need 2 cables???
One floppy drive cable should not enable the controller to talk to the drives at all.
Phil
Anybody here interested in a bunch of Digital VAX Rdb/VMS books ?
Quite a few are still sealed. I prefer to sell them because I need the
space and could use any extra money but I am willing to swap them for
something else or perhaps even give them to someone for just the postage.
Cheers,
Stefan.
-------------------------------------------------------
http://www.oldcomputercollection.com
