• Please review our updated Terms and Rules here

old hard disk

S

sharad

New Member
Joined
Sep 14, 2007
Messages
1
im using machine only support NEC 3142 and NEC 5146 (40 MB)hard disk ST506 interface .how can i use another hard disk which are available now days instead of these .what hardware and software changes i have to be made for that.
 
sharad said:
im using machine only support NEC 3142 and NEC 5146 (40 MB)hard disk ST506 interface .how can i use another hard disk which are available now days instead of these .what hardware and software changes i have to be made for that.
Click to expand...

Hi
There were differring types of interfaces from the computer side.
Most popular for this time period was the WD1000 type interface.
This type of interface is actually similar from a software point of view
to the more common IDE interface. There was another HD interface
used on the AT type PC's that was not compatable that was used
for MFM drives.
The main issue with using a IDE is to format it and to create the interface.
Many IDE drives can automatically configure to the same head and cylinder
numbers you need.
Another possibility is to us a CompactFlash. These can be configured to
look like a IDE drive. There is a way to specify to the CF what you want
the drive to look like. One can look this up in the CF specification that
can be found on the web someplace.
Both of these options can be done with a minimum of additional hardware
because all the IDE needs is bus buffers and an address decoder. This
will most likely be software compatable as well.
CF cards and IDE have another issue and that is that they number the
cylinders from 1 instead of 0. This can often be patched by adding an
increment to the code that generated cylinder number.
Another option would be to locate another MFM drive of similar size.
The problem is that 8 head drives ( what you have ) are just not that
common. The ST251 is an 6 head drive and could be used with software
changes. It does have the right size and these are more common.
Many machines had tables somewhere to be used to calculate drive
head/cylinder/sector. If this can be located, one can simply change
the values.
One does have to be careful about stepping speed. If the system is
not using auto stepping with the NEC, it may expect a faster step rate
than the ST251 can handle. This can usually be fixed by using the auto
step mode.
These both require a few days of decoding the HD software driver. I've done
this for an Olivetti M20 but it is still a lot of work.
Dwight
 
Or, you could use a modern SCSI drive with a BIOS based SCSI card, set your hard drives to none for both in the computer BIOS and let the card handle everything.
 
Last edited:
Druid6900 said:
Or, you could use a modern SCSI drive with a BIOS based SCSI card, set your hard drives to none for both in the computer BIOS and let the card handle everything.
Click to expand...

Hi
I don't think he specified the type of machine he is using.
There never was a SCSI card for my M20 as an example.
Dwight
 
Druid6900 said:
Doesn't the M20 have ISA slots?

I know my M25 does.
Click to expand...

The M20 isn't a x86 machine ( although there was an add-on card that
had a 8086 on it ). The M20 is a Z8000 machine. It was designed in
Cupertino, Ca. because of the close distance to Zilog. It was designed
about the same time as the IBM PC but didn't make it to the market
with enough time to be popular.
It was used quite a bit in Italy and Germany, especially for scientific
work.
There was a CP/M-8000 release from DR for it as well. It was almost
lost to time except, Al Kossow found some 8 inch disk with enough on
them to rebuild a boot disk for the M20 ( 5-1/4 disk ). Chris Groessler
and I worked on restoring this data to run on the M20.
The machine does a few things that could have been done on the PC
but were not. The one I like is splitting the data and code into two
different segments. This leaves a clean 64K for data. It wasn't
until the 286 that the PC could handle multiple segements, even
though the 8086 could with a smal amount of hardware help.
The M20's rarely come up on eBay here in the US. Most people wouldn't
even realized that it was special compared to other M series Olivettis.
I've only see one come up in the US, on eBay, in the last 5 years and I bought
it for $75. They do come up about once a month on the Italian eBay.
These tend to go for 100 to 200 euros, depending on what else comes
with them.
They are a cool machine if one wants to fiddle with Z8000s. It has
a BASIC based on uSoft BASIC and well as an assembler. The operating
system is called PCOS. We also have CP/M-8000 running as well, now.
This is similar to the CP/M-68K. It will take most of the C source code
that was written for the 68K and compile to executables.
If one is interested in the work I and others have done with the M20,
check out:

http://www.z80ne.com/m20/index.php

later
Dwight
 
Well, that is quite interesting and the second interesting thing I've found out about Olivetti recently.

The first was that they were the ones that made the AT&T 6300. AT&T just re-badged it.

If the OP ever shows up again, we can see what he is using and advise him accordingly.
 
Druid6900 said:
Well, that is quite interesting and the second interesting thing I've found out about Olivetti recently.

The first was that they were the ones that made the AT&T 6300. AT&T just re-badged it.

If the OP ever shows up again, we can see what he is using and advise him accordingly.
Click to expand...

Hi
One of the Radio Shack machines was an Olivetti but I forget which.
Dwight
 
You must log in or register to reply here.
Back
Top