SCSI to IDE
joe lobocki jlobocki
<mailto:cctalk%40classiccmp.org?Subject=Re%3A%20SCSI%20to%20IDE&In-Reply-To=
%3CAANLkTinO5OZGqmp_tiokWNnqYD_e7AAwKDE7ALoG2_8%2B%40mail.gmail.com%3E> at
gmail.com
Fri Nov 26 10:48:01 CST 2010
* Previous message: AT
<http://classiccmp.org/pipermail/cctalk/2010-November/294377.html> &T 3B1
Unix PC Boot ROMs
* Next message: SCSI to IDE
<http://classiccmp.org/pipermail/cctalk/2010-November/294385.html>
* Messages sorted by: [ date ]
<http://classiccmp.org/pipermail/cctalk/2010-November/date.html#294382> [
thread ]
<http://classiccmp.org/pipermail/cctalk/2010-November/thread.html#294382> [
<http://classiccmp.org/pipermail/cctalk/2010-November/subject.html#294382>
subject ] [ author ]
<http://classiccmp.org/pipermail/cctalk/2010-November/author.html#294382>
_____
Ok, so I have been doing research, and this affects everyone here who
collects SGI, apple, and anything using scsi. in the near future, the supply
of smaller SCSI drives will eventually dry up, due to failure from age and
lack of supply, as I believe they are no longer manufactured, unless for the
industrial/server market. I could be wrong on that part, but I take it as
such because my searching for them brings up nothing new. what does that
mean for collectors? it means that your neat little apple or SGI or etc will
run, until the scsi disk dies, then we will be left cannibalizing machines
for disks, paying ridiculous prices for leftover scsi disks, which will
skyrocket because of the small supply.
So what is our option? I have seen SCSI to IDE adapters around, but they go
up into the $100's to $200's, say you have a minimum 10 machines, that
leaves you somewhere between $1,000 and $2,000 total, before the disk or
devices. If we could design a simple SCSI to IDE interface, we could be set
for a good long while on storage for these devices for a decent amount of
time. There are all sorts of adapters to IDE, there is CF to IDE, SD to IDE,
SD to CF which could be placed in a CF to IDE adapter if need be, i'm sure
one could also rig up a USB drive to SCSI if one tried, but I could be
wrong.
Having said that, I know nothing about programming microcontrollers or
simple processors, but I have seen people on the board who do. I'm sure if
we can find a chip capable, and lay out a schematic, source code, and
possibly a board layout, members could source their own boards and
components to build their own devices at home (given they have a chip
programmer), so no one person has to take on the responsibility of supplying
parts, kits, finished devices unless they so choose to. This is just an
idea, if nothing becomes of it, no big deal, just putting it out there....
-Joe
_____
* Previous message: AT
<http://classiccmp.org/pipermail/cctalk/2010-November/294377.html> &T 3B1
Unix PC Boot ROMs
* Next message: SCSI to IDE
<http://classiccmp.org/pipermail/cctalk/2010-November/294385.html>
* Messages sorted by: [ date ]
<http://classiccmp.org/pipermail/cctalk/2010-November/date.html#294382> [
thread ]
<http://classiccmp.org/pipermail/cctalk/2010-November/thread.html#294382> [
<http://classiccmp.org/pipermail/cctalk/2010-November/subject.html#294382>
subject ] [ author ]
<http://classiccmp.org/pipermail/cctalk/2010-November/author.html#294382>
_____
More information <http://www.classiccmp.org/mailman/listinfo/cctalk> about
the cctalk mailing list
_____
-----REPLY-----
Hi! I am willing to make a PCB and offer it as part of the N8VEM home brew
computer project. If someone would send me a design I will be glad to make
a schematic, PCB layout, and get a small number of prototype boards. This
could be a simple circuit comprised of a Z80 with three 8255 PPIs, RAM and
ROM (one 8255 for IDE, two 8255s for SCSI-2) or a more complex
microcontroller scheme.
Please contact me if interested. Thanks and have a nice day!
Andrew Lynch
Now that I have access to the main unit the plot thickens. All of the
outputs of the potted brick go to full-wave bridge rectifiers in the main
unit such that you get a plus and minus voltage reference to the CT ( center
tap ). That big potted POS is nothing more than a big friggin transformer !
The main output leads ( 1 2 and 3 ) have 28 VAC coming out of them. I put a
Variac on the " transformer " and turned it up very slowly. At not much
voltage it gets very HOT ( I suspect shorted windings or a whole shorted
primary on the input side. The 28 VAC output figure came from estimating
proportionally what the output voltage would be with a full 115 VAC on the
input primary. I own this puppy now !!
Best regards, Steven
> As somebody elase said, I think you have to read the data regiater too.
Ok, I improved my test program to read the data reg and also give some visual feedback:
LDAA #$10 ; like in JBUG
STAA $8008 ; ACIA control
STAA $8022 ; enable 1 digit leds
LOOP LDAA #$7F
STAA $8020 ; clear display
READ LDAA $8008 ; ACIA status
ASRA
BCC READ ; data ready?
LDAB $8009 ; ACIA data
STAA $8020 ; display status
LDX #$0100 ; delay
DELAY DEX
BNE DELAY
CMPB #'G ; EOT?
BNE LOOP
SWI
The idea is to light a digit for a brief period when a byte is read and have
the segments show the status register. Also it should exit if it received
the "G". Ok, the G may be *in* a data block but I hardly ever found a G anyway.
At least it allows me to tune the volume until I receive something. But it looks
random and looking at the leds, like half of the bytes read are framing errors.
Obviously, I varied what I could think of (delay, "G", ...) used several
recorders (2PCs with audacity, a real cassette deck and two audio cables)
> I assume you have the manual for this evaluation kit. It's on bitsavers
> if you don't. It explains how the cassette interface circuitry works in
> some detail, and is well worth reading.
Yes, I have the manual and read it through.
> I asusme you intiialising the 6850 correctly, and that you're settign
> that 4053 analoge switch properly,. If not, it can never work.
I'm initialising it by writing $10 in the control reg, which I copied from
the JBUG listing.
I don't find any reference of a "4053" or similar in the docs of the kit.
> Do you have a (real [1]) tape recorder? If so, try saving something.
> Listen to the recording, does it sound like the typical 'burble'? And try
> loading it. Point being if there's something wrong with how you're playing
> the audio files you could have problems.
Yes, dug up my Realistic cassette recorder that came with my TRS-80 but it
didn't help.
The samples I'm trying to load are recorded with the kit itself. They sound
typical and I was able to decode them to binary. As a test, I decoded the
jbug rom and compared it to the file from bitsavers. It matched! (except for 4
bytes near the end which are zero on bitsavers an are actually different on
my rom). That made me conclude that the 'punch' function is working and the
samples I'm using are good. I would like to test with a known-good audio
file but I can't find any...
I must point out that the kit is expanded and I haven't figured out what it is
exactly. The wirewrap area on the processor board has two extra ACIAs and a
crystal. I understand the original was a 614.4, this seemed to be replaced
by 1MHz and the 614.4 used for the other ACIAs. Anyway, I already swapped
them (which did make me type less double characters since I guess the keyboard
scan delay is chosen for the original clock speed). The kit came with a Philips
Mini-DCR and the cables seem to be made to connect that on the J1 I/O connector.
I could go the route of restoring that, but it seems more challenging and
it wouldn't allow me to transfer data with the outside world.
But I'd like to get at least to the point that I can load and run a program without
having to type it in...
I also read that the kit allows to connect RS-232, that would be ideal but I don't
see how that's possible without adding components and wiring.
Wim.
Here's another idea that'll get me a place in the Loony Bin.
A little while ago I picked up a couple of Amstrad EME232 double-sided
3-inch floppy drives. Out of the three I have, two have had their
read-write ASIC zapped by someone (in one case myself, in another an
ebay seller) plugging them into a PC power supply to "test". Net result:
the ASIC goes completely deaf.
Let's assume for a minute that the heads in the EME232 drives are
undamaged. That means all the issues are related to defective circuitry
on the PCB. So, how about this for an idea: move the controller chip and
surrounding circuitry (or even the whole board) to the EME232, then wire
it into the existing drive mechanics.
This would -- in theory -- allow the two dead 232s (and possibly the
EME156 single-head drive) to be resurrected.
Anyone care to comment on this idea and its possibility or absurdity?
The other option would be to get a new read-write ASIC for the Amstrad
drives, but those seem to be like hen's teeth. Part number is M51017AP
(made by Panasonic but if memory serves they're not marked with a logo
or manufacturer designation) if anyone wants to check.. :)
Thanks,
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
There is an HP9845B computer with a large hard drive available for pickup in northern Maine.
***Contact the owner (Terry Helms) directly at: mainehiker at gmail.com; ***
Please don't email me, I just told you everything I know about it :)
Here is the picture he sent me.
http://i1181.photobucket.com/albums/x426/DrCharlesMorris/IMG_4102HP9845Bcom…
Hope someone in New England can rescue this interesting looking system.
thanks
Charles
Well, I've unpacked the AViiON and the Microdata 1600 inside, but it
looks like I won't be able to look at them for at least a week or two.
My lady and I are leaving in moments for YET ANOTHER trip up north
(we've been home for less than a week!) due to someone's passing.
I love driving, but enough is enough. My cats will never forgive me.
Maybe some new goodies will come my way on this trip like last time.
I'll be going up 95, then into West ("By God!") Virginia and staying
there for several days, perhaps a week. I'll be driving a mostly-empty
car. ;)
-Dave
--
Dave McGuire
Port Charlotte, FL
Hi guys,
Here's a treat for the 3B1 owners in the audience: images of the two
Boot PROMs...
<http://www.philpem.me.uk/code/3b1emu/3b1_roms.zip>
Thanks are due to Michael Lee for providing the ROMs, and to Steven
Hirsch for scanning the 3B1 TechRef, which started me out on this nutty
little "write a 3B1 emulator" project...
Enjoy!
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
