Using 1.44MB usb drive as drives for pidp-11 , Possible

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Warren Hardy

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May 21, 2021, 6:08:36 PM5/21/21

to [PiDP-11]

I want to make my pidp-11 seem a bit more real, I like the idea of removable disks. I was wondering if anybody use USB 3.5 floppy drives.

I like the idea of have peripherals.

I am very unskilled when it comes to simh. Is it possible to configure simh for the pip-11 see the floppy drives as dec drives?

Is it possible then to format a drive the copy the OS and software over to the drive, (or can you dd the image onto a floppy?

Systems I am interested in playing around this was is BSD 2.2 and RT-11.

Johnny Billquist

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May 21, 2021, 6:26:22 PM5/21/21

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Should be possible. But it will be ugly slow.

At least when running under some Unix system, I would expect if you just
take an MSCP disk, point it at the raw floppy device, and off you go.
I would expect that it should correctly figure out the size, and that
then becomes the size the MSCP disk appears to be inside simh, and all
software can deal with it.

The one thing I suspect might not work right is that in MSCP there are
commands to spin down the disk, which could (in theory) result in the
floppy being ejected. But I'd be really surprised if that actually
worked. But it would be cool.

And yes, of course you can use dd towards a floppy. But the image you
write down to it needs to match in size, or else things will probably
look funny.

Johnny

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|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
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Ed Groenenberg

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May 25, 2021, 12:38:36 PM5/25/21

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Yes, you can, provided the USB device is visible in /dev.

I uses an USB based Iomega 100Mb zidrive, and is did show up in /dev, i can't remember the exact name right now)

In SIMH I then attach it at 'set rq2 /dev/<iomega_dev>
and 'set rq2 rasize=100M' or something similar.

Then just use SIMH.

Ejecting is not possible, as SIMH holds the drive 'open'. You might need to write an 'EXPECT' command script in SIMH
to detect unmounting sequence in SIMH, then have the floppy ejected and resume work in SIMH again.

Ed
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Mark Matlock

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May 25, 2021, 12:38:43 PM5/25/21

to Warren Hardy, [PiDP-11]

Warren,
I have seen RT-11 run from (non-USB) 3.5 inch floppy drives in a system that Malcolm Macleod
exhibited at the 2019 VCF MW. He had the 4 slot open backplane with CPU, Memory, Serial port
and a RQDX3 (if I remember right) which ran the 1.44 MB floppies His site describes using the
RQDX3 with a TEAC FD-55GFR 1.2 MB drive at https://avitech.com.au/?page_id=2660

To use a USB floppy drive from Simh on a PC is quite different however, There is a raw I/O
capability in Simh but I can’t seem to find much documentation for it, but that would be the
area to explore. It also is likely to be easier with Linux than Windows.

Good Luck,
Mark

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Johnny Billquist

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May 25, 2021, 6:32:29 PM5/25/21

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On 2021-05-22 19:04, Mark Matlock wrote:
> Warren,
> I have seen RT-11 run from (non-USB) 3.5 inch floppy drives in a system that Malcolm Macleod
> exhibited at the 2019 VCF MW. He had the 4 slot open backplane with CPU, Memory, Serial port
> and a RQDX3 (if I remember right) which ran the 1.44 MB floppies His site describes using the
> RQDX3 with a TEAC FD-55GFR 1.2 MB drive at https://avitech.com.au/?page_id=2660

That would be identified as an RX33, I would expect. Which is supported.

> To use a USB floppy drive from Simh on a PC is quite different however, There is a raw I/O
> capability in Simh but I can’t seem to find much documentation for it, but that would be the
> area to explore. It also is likely to be easier with Linux than Windows.

Yeah, I'm sortof also thinking along the lines of raw I/O interfacing. I
haven't looked at it in simh though.

Johnny

>
> Good Luck,
> Mark
>
>> On May 21, 2021, at 5:08 PM, Warren Hardy <hellfi...@gmail.com> wrote:
>>
>> I want to make my pidp-11 seem a bit more real, I like the idea of removable disks. I was wondering if anybody use USB 3.5 floppy drives.
>>
>> I like the idea of have peripherals.
>>
>> I am very unskilled when it comes to simh. Is it possible to configure simh for the pip-11 see the floppy drives as dec drives?
>> Is it possible then to format a drive the copy the OS and software over to the drive, (or can you dd the image onto a floppy?
>>
>> Systems I am interested in playing around this was is BSD 2.2 and RT-11.
>>
>>
>> --
>> You received this message because you are subscribed to the Google Groups "[PiDP-11]" group.
>> To unsubscribe from this group and stop receiving emails from it, send an email to pidp-11+u...@googlegroups.com.
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>

matt...@ep1.rub.de

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May 27, 2021, 4:49:02 PM5/27/21

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Hi everybody,

if it's possible to use a floppy via simh from RSX running on a pidp-11, would it work to connect a QIC-80 floppy tape via a USB/floppy adapter to the RPi in my pidp-11 and use it as a tape in RSX? I have a QIC-80 drive and some tapes, and it would be cool to write some data to a real tape. ... I think I'll order an USB/floppy adapter and bring the tape drive to work with my linux desktop.

Greetings,

Matthias

Johnny Billquist

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May 27, 2021, 5:02:36 PM5/27/21

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The QIC-80 might physically be a tape, but it behaves like a floppy, so
you can't use it like a tape.
Tapes and floppies (or any disks) are very different in their properties.
The QIC-80 is very similar to a DECtape II. Might be almost identical
physical construction, but the capacity of the DECtape II is much less.

But the basic answer in the end is no. Anything that hooks up to a
floppy controller will never be possibly to manage like a tape.

Johnny

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>
> >
>
> --
> Johnny Billquist || "I'm on a bus
> || on a psychedelic trip
> email: b...@softjar.se || Reading murder books
> pdp is alive! || tryin' to stay hip" - B. Idol
>

> <mailto:pidp-11+u...@googlegroups.com>.

> To view this discussion on the web visit

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matt...@ep1.rub.de

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May 28, 2021, 5:51:48 AM5/28/21

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Hi Johnny,

thanks for the prompt answer. If the QIC-80 is very similar to a DECtape II, is it possible to use it as a DECtape? Not necessarily out-of-the-box, but maybe with an extension to simh?

Greetings,

Matthias

Johnny Billquist

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May 28, 2021, 8:09:14 AM5/28/21

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Well. First of all, DECtape looks like a disk. Like a very slow floppy,
you could say.

Second, DEC software only understands the RX50 and the standard 1.2M
DD/DS floppy, which DEC calls an RX33. No other types are understood.

But you could just connect it up as a normal MSCP disk of arbitrary
size. From the PDP-11 point of view, there is no need to expose any
particular oddities. It will just be a very slow disk. But that should
work fine, as long as the host system can access it as a floppy, which I
suspect it can.

Johnny

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>
>
> --
> Johnny Billquist || "I'm on a bus
> || on a psychedelic trip
> email: b...@softjar.se || Reading murder books
> pdp is alive! || tryin' to stay hip" - B. Idol
>

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matt...@ep1.rub.de

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May 28, 2021, 12:39:52 PM5/28/21

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Hi Johnny,

I ordered an USB/floppy adapter (from China) and will try the MSCP disk.

Greetings,

Matthias

Johnny Billquist

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May 28, 2021, 1:40:05 PM5/28/21

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Ok.
My main question at this point is only: why?

Just hook up any USB disk (or even USB stick) directly to your computer,
and use that instead. It's faster, have larger capacity, and can be
moved around as easily. Is available in the closest shop, and is
probably cheaper.

Johnny

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>
>
> --
> Johnny Billquist || "I'm on a bus
> || on a psychedelic trip
> email: b...@softjar.se || Reading murder books
> pdp is alive! || tryin' to stay hip" - B. Idol
>

> https://groups.google.com/d/msgid/pidp-11/80d5a490-a491-4014-baec-b95245eff34fn%40googlegroups.com
> <https://groups.google.com/d/msgid/pidp-11/80d5a490-a491-4014-baec-b95245eff34fn%40googlegroups.com?utm_medium=email&utm_source=footer>.

Louis Smith

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May 28, 2021, 1:51:10 PM5/28/21

to Johnny Billquist, [PiDP-11]

What about the old (but still available) Zip drives configured as removable hard drives?

They truly were a hard platter in a removable sleeve/case, and the latest incarnation was USB enabled.

Louis

To view this discussion on the web visit https://groups.google.com/d/msgid/pidp-11/e1e82cc3-7ef8-6443-c947-ef0e21a605a0%40softjar.se.

Johnny Billquist

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May 28, 2021, 2:05:59 PM5/28/21

to Louis Smith, [PiDP-11]

They will also work in the sense that you can make a disk image sit on
it, and make that available for the PDP-11.

The actual details of the disk on the host system are irrelevant. If the
host system can access the disk, you can then expose that to simh, or
whatever. And for simh, you can present it as any type of disk you want.

If you want to hand over the raw disk, that is usually no different,
except then of course you don't have a disk image on the disk, but you
just hand over the whole disk.

The point is still that the actual interfacing to the real disk is
handled by the host operating system, which hides away such details.
simh in turn is just dealing with an abstracted disk, and will in turn
present to the simulated pdp-11 a disk using whatever controller you
want. MSCP is just more useful than most, since it allows the disk to be
of an arbitrary size, while most other disks have a fixed size, which
might either not fit on your host disk, or might just waste parts of it.

Johnny

On 2021-05-28 19:50, Louis Smith wrote:
> What about the old (but still available) Zip drives configured as
> removable hard drives?
>
> They truly were a hard platter in a removable sleeve/case, and the
> latest incarnation was USB enabled.
>
> Louis
>
>
>
> On Fri, May 28, 2021 at 1:40 PM Johnny Billquist <b...@softjar.se
> <mailto:b...@softjar.se>> wrote:
>
> Ok.
> My main question at this point is only: why?
>
> Just hook up any USB disk (or even USB stick) directly to your
> computer,
> and use that instead. It's faster, have larger capacity, and can be
> moved around as easily. Is available in the closest shop, and is
> probably cheaper.
>
> Johnny
>

> On 2021-05-28 18:39, matt...@ep1.rub.de <mailto:matt...@ep1.rub.de>

> wrote:
> > Hi Johnny,
> > I ordered an USB/floppy adapter (from China) and will try the
> MSCP disk.
> > Greetings,
> > Matthias
> >
> >

> > b...@softjar.se <mailto:b...@softjar.se> schrieb am Freitag, 28.

> Mai 2021 um 14:09:14 UTC+2:
> >
> > Well. First of all, DECtape looks like a disk. Like a very
> slow floppy,
> > you could say.
> >
> > Second, DEC software only understands the RX50 and the
> standard 1.2M
> > DD/DS floppy, which DEC calls an RX33. No other types are
> understood.
> >
> > But you could just connect it up as a normal MSCP disk of
> arbitrary
> > size. From the PDP-11 point of view, there is no need to
> expose any
> > particular oddities. It will just be a very slow disk. But
> that should
> > work fine, as long as the host system can access it as a floppy,
> > which I
> > suspect it can.
> >
> > Johnny
> >
> > On 2021-05-28 11:51, matt...@ep1.rub.de

> <mailto:matt...@ep1.rub.de> wrote:
> > > Hi Johnny,
> > > thanks for the prompt answer. If the QIC-80 is very
> similar to a
> > DECtape
> > > II, is it possible to use it as a DECtape? Not necessarily
> > > out-of-the-box, but maybe with an extension to simh?
> > > Greetings,
> > > Matthias
> > >
> > >

> > > b...@softjar.se <mailto:b...@softjar.se> schrieb am

> Donnerstag, 27. Mai 2021 um 23:02:36
> > UTC+2:
> > >
> > > The QIC-80 might physically be a tape, but it behaves like a
> > floppy, so
> > > you can't use it like a tape.
> > > Tapes and floppies (or any disks) are very different in their
> > > properties.
> > > The QIC-80 is very similar to a DECtape II. Might be almost
> > identical
> > > physical construction, but the capacity of the DECtape II
> is much
> > less.
> > >
> > > But the basic answer in the end is no. Anything that hooks
> up to a
> > > floppy controller will never be possibly to manage like a
> tape.
> > >
> > > Johnny
> > >
> > >
> > >
> > > On 2021-05-27 22:49, matt...@ep1.rub.de

> <mailto:matt...@ep1.rub.de> wrote:
> > > > Hi everybody,
> > > > if it's possible to use a floppy via simh from RSX
> running on a
> > > pidp-11,
> > > > would it work to connect a QIC-80 floppy tape via a
> USB/floppy
> > > adapter
> > > > to the RPi in my pidp-11 and use it as a tape in RSX? I
> have a
> > > QIC-80
> > > > drive and some tapes, and it would be cool to write some
> data to
> > > a real
> > > > tape. ... I think I'll order an USB/floppy adapter and
> bring the
> > > tape
> > > > drive to work with my linux desktop.
> > > > Greetings,
> > > > Matthias
> > > >
> > > >

> > > > b...@softjar.se <mailto:b...@softjar.se> schrieb am

> <hellfi...@gmail.com <mailto:hellfi...@gmail.com>>

> > > > wrote:
> > > > >>
> > > > >> I want to make my pidp-11 seem a bit more real, I
> like the idea
> > > > of removable disks. I was wondering if anybody use USB
> 3.5 floppy
> > > > drives.
> > > > >>
> > > > >> I like the idea of have peripherals.
> > > > >>
> > > > >> I am very unskilled when it comes to simh. Is it
> possible to
> > > > configure simh for the pip-11 see the floppy drives as
> dec drives?
> > > > >> Is it possible then to format a drive the copy the OS and
> > > > software over to the drive, (or can you dd the image onto a
> > floppy?
> > > > >>
> > > > >> Systems I am interested in playing around this was is
> BSD 2.2
> > > > and RT-11.
> > > > >>
> > > > >>
> > > > >> --
> > > > >> You received this message because you are subscribed
> to the
> > > > Google Groups "[PiDP-11]" group.
> > > > >> To unsubscribe from this group and stop receiving
> emails from
> > > > it, send an email to pidp-11+u...@googlegroups.com

> <mailto:pidp-11%2Bu...@googlegroups.com>.

> > > > >> To view this discussion on the web visit
> > > >
> > >
> >

> > > > email: b...@softjar.se <mailto:b...@softjar.se> ||

> Reading murder books
> > > > pdp is alive! || tryin' to stay hip" - B. Idol
> > > >
> > > > --
> > > > You received this message because you are subscribed to
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> > > send
> > > > an email to pidp-11+u...@googlegroups.com

> <mailto:pidp-11%2Bu...@googlegroups.com>
> > > > <mailto:pidp-11+u...@googlegroups.com
> <mailto:pidp-11%2Bu...@googlegroups.com>>.

> > > email: b...@softjar.se <mailto:b...@softjar.se> || Reading

> murder books
> > > pdp is alive! || tryin' to stay hip" - B. Idol
> > >
> > > --
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> the Google
> > > Groups "[PiDP-11]" group.
> > > To unsubscribe from this group and stop receiving emails
> from it,
> > send
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> <mailto:pidp-11%2Bu...@googlegroups.com>>.

> > email: b...@softjar.se <mailto:b...@softjar.se> || Reading

> murder books
> > pdp is alive! || tryin' to stay hip" - B. Idol
> >
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> > To view this discussion on the web visit
> >
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>
> --
> Johnny Billquist || "I'm on a bus
> || on a psychedelic trip

> email: b...@softjar.se <mailto:b...@softjar.se> ||

> Reading murder books
> pdp is alive! || tryin' to stay hip" - B. Idol
>
> --
> You received this message because you are subscribed to the Google
> Groups "[PiDP-11]" group.
> To unsubscribe from this group and stop receiving emails from it,
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