15 Dec
2018
15 Dec
'18
11:17 a.m.
Hi,
the Epson HX-20 handheld computer offered an interesting way to connect
it with peripheral devices. The serial port at the back of the computer
can talk to external hardware using an Epson-specific protocol for data
exchange. As this protocol is quite well documented, I wrote a little
program called "flashx20" (for FLoppy And Screen for the HX-20), which
allows to connect a normal Windows PC or notebook computer to the HX-20,
where the PC interprets the Epson serial protocol and simulates an
external display controller and four external floppy disk drives (like
e.g. the Epson TF-20).
With that, you get a big screen (the PC monitor) and disk space for
programs and data on the PC's hard disk, which can then also be used for
data and program exchange.
You can read more about it and download the program from my website at
http://members.aon.at/nkehrer/
Norbert
16 Dec
16 Dec
1:10 a.m.
On Sat, Dec 15, 2018 at 5:47 PM Norbert Kehrer via cctalk
<cctalk at classiccmp.org> wrote:
With that, you get a big screen (the PC monitor) and
disk space for
programs and data on the PC's hard disk, which can then also be used for
data and program exchange.
This is great - thank you for writing it! I have at least one HX-20.
IIRC it was used for Motorola radio programming and had custom ROMS.
Do you know what other Epson portables (if any) used the same protocol?
1:21 a.m.
On Sat, Dec 15, 2018 at 5:47 PM Norbert Kehrer via
cctalk
<cctalk at classiccmp.org> wrote:
> With that, you get a big screen (the PC monitor) and disk space for
> programs and data on the PC's hard disk, which can then also be used for
> data and program exchange.
On Sun, 16 Dec 2018, Jason T via cctalk wrote:
This is great - thank you for writing it! I have at
least one HX-20.
IIRC it was used for Motorola radio programming and had custom ROMS.
Do you know what other Epson portables (if any) used the same protocol?
The Epson HC-20 probably did.
It was essentially the same machine, in silver-grey, instead of beige,
with both English and katakana keyboard and character generator ROMs.
5:44 a.m.
/On Sat, Dec 15, 2018 at 5:47 PM Norbert Kehrer via
cctalk />/<cctalk at classiccmp.org
<http://www.classiccmp.org/mailman/listinfo/cctalk>> wrote: />>/With
that, you get a big screen (the PC monitor) and disk space for />>/programs and data
on the PC's hard disk, which can then also be used for />>/data and program
exchange. /
On Sun, 16 Dec 2018, Jason T via cctalk wrote:
/This is great - thank you for writing it! I have at
least one HX-20. />/IIRC it was used for Motorola radio programming and had custom
ROMS. />/Do you know what other Epson portables (if any) used the same protocol? /
On Sun, 16 Dec 2018, Fred Cisin via cctalk wrote:
The Epson HC-20 probably did.
It was essentially the same machine, in silver-grey, instead of beige,
with both English and katakana keyboard and character generator ROMs.
I have not tested it, but I suppose, that also the PX-8 and PX-4 used the protocol,
because the protocol specification defines the following device numbers:
- HX-20: 0x20 (probably also used for the HC-20)
- PX-8: 0x22
- PX-4: 0x23
10:59 p.m.
On Sun, 16 Dec 2018, Norbert Kehrer via cctalk wrote:
I have not tested it, but I suppose, that also the
PX-8 and PX-4 used the
protocol,
because the protocol specification defines the following device numbers:
- HX-20: 0x20 (probably also used for the HC-20)
- PX-8: 0x22
- PX-4: 0x23
That is especially interesting.
It is probable that the HX-20 worked with the TF20 on a file level load
and save, but the PX-8 was likely to work on a sector level.
The HC-20s that I had were Japanese machines brought to USA for some
software develpment in Berkeley. HudsonSoft?
The HX20 never caught on very well in USA. It had a few dedicated
applications, such as CableTV configuration.
There was no technical documentation available.
I had a little bit of incomplete Japanese documentation.
During the time that I had some machines, the technical manual and
protocol specification were unavailable in USA.
I don't remember the disk format for the TF20 external drives, and
they were unavailable in USA. IIRC, the only sample disk that I had used
a form of the Microsoft "Stand-Alone BASIC", much closer to the NEC
variants than the Coco. (seek center directory, with short directory
entries that included a starting cluster number, and a linked list Granule
Allocation Table (similar to MS-DOS FAT, and early Mac disk format)
DSDD, with 16 256 byte sectors per track (320K)
The Epson Geneva PX-8 had an external 3.5" floppy available, and CP/M!
However, the PX-8 3.5" had 40 cylinders, with 67.5 tpi, instead of the
common 80 cylinder 135 tpi of other 3.5" disks.
Those 40 cylinder 3.5" drives are quite rare.
I don't know about the track width; for reading, a PC can simply look at
every other track. And formatting a virgin disk and writing to it should
work. But, there is a definite possibility that RE-writing a PX-8 disk
would result in one that the PX-8 couldn't handle (EXACTLY the same
problem as RE-writing a 40 track 5.25" disk with an 80 track 5.25" drive)
With appropriate format handling software on the PC, it should be
possible for a PC connected using your system to work with actual Epson
diskettes, and emulate the Epson external drives.
Thank you for creating this!
Now, I wish that I had been able to keep the HC-20s!
--
Grumpy Ol' Fred cisin at xenosoft.com
11:14 p.m.
On 12/16/2018 10:59 PM, Fred Cisin via cctalk wrote:
On Sun, 16 Dec 2018, Norbert Kehrer via cctalk wrote:
PX-8!
I have not tested it, but I suppose, that also
the PX-8 and PX-4 used
the protocol,
because the protocol specification defines the following device numbers:
- HX-20: 0x20 (probably also used for the HC-20)
- PX-8:? 0x22
- PX-4:? 0x23
The Epson Geneva PX-8 had an external 3.5" floppy
available, and CP/M!
CP/M was in rom so your disk was a paltry 24k(bare PX8),
60K(multiwedge)
or 120K (Ramdisk wedge)
and of course both a 5.25 or 3.5 floppy.? The 3.5" drive could run on
internal battery.
However, the PX-8 3.5" had 40 cylinders, with
67.5 tpi, instead of the
common 80 cylinder 135 tpi of other 3.5" disks.
Those 40 cylinder 3.5" drives are quite rare.
I don't know about the track width; for reading, a PC can simply look
at every other track.? And formatting a virgin disk and writing to it
should work.? But, there is a definite possibility that RE-writing a
PX-8 disk would result in one that the PX-8 couldn't handle (EXACTLY
the same problem as RE-writing a 40 track 5.25" disk with an 80 track
5.25" drive)
Many of the drives have dead spots and need a manual push to start.? I
have two like that.? I suspect the
ceramic magnet lost its stuff over time.? When I have time the next
project will be a Atmega2650 running
a CF to via serial interface.? The drive table can be patched for a
larger (up to 8mb) drive.
With appropriate format handling software on the PC, it should be
possible for a PC connected using your system to work with actual
Epson diskettes, and emulate the Epson external drives.
There are several software packages on the net to do the fake of the
disk via serial and manuals of the system to
explain the format.? Likely that software could do the earlier HX20 (and
friends) with minor tweaks.
Allison
11:39 p.m.
> However, the PX-8 3.5" had 40 cylinders,
with 67.5 tpi, instead of the
> common 80 cylinder 135 tpi of other 3.5" disks.
> Those 40 cylinder 3.5" drives are quite rare.
Somewhere in my searches I
recall reading that the 3 1/2" drives used the same format as the 5 1/4" ones.
Maybe 40 tracks of 16 256 byte sectors. Oddly, I believe that 2 tracks are "reserved
for CP/M" even though it is in ROM and not stored on disk.
ceramic magnet lost its stuff over time.? When I have
time the next
project will be a Atmega2650 running
a CF to via serial interface.? The drive table can be patched for a
larger (up to 8mb) drive.
I've been planning something very similar for a
while, but using an Arduino (ATMega 328) or bare AVR chip and probably a smaller/simpler
flash chip. I din't know about the drive table. That's interesting. Would a new
ROM have to be burned with the new table? Do you have an links to the info?
With appropriate format handling software on the PC, it should be
possible for a PC connected using your system to work with actual
Epson diskettes, and emulate the Epson external drives.
There are several software packages on the net to do the fake of the
disk via serial and manuals of the system to
explain the format.? Likely that software could do the earlier HX20 (and
friends) with minor tweaks.
11:56 p.m.
On December 16, 2018 at 11:14 PM allison via cctalk
<cctalk at classiccmp.org> wrote:
A subject dear to me. I still have the px-8 I bought new (borrowed the money from
my sister) as a young man in 1984. Alas, I could never afford the PF-10 disk drive.
>> However, the PX-8 3.5" had 40 cylinders, with 67.5 tpi, instead of the
>> common 80 cylinder 135 tpi of other 3.5" disks.
>> Those 40 cylinder 3.5" drives are quite rare.
On Sun, 16 Dec 2018, Will Cooke via cctalk wrote:
On Sun, 16 Dec 2018, Norbert Kehrer via cctalk
wrote:
PX-8!
I have not tested it, but I suppose, that also
the PX-8 and PX-4 used
the protocol,
because the protocol specification defines the following device numbers:
- HX-20: 0x20 (probably also used for the HC-20)
- PX-8:? 0x22
- PX-4:? 0x23
Somewhere in my searches I recall reading that the 3
1/2" drives used
the same format as the 5 1/4" ones. Maybe 40 tracks of 16 256 byte
sectors. Oddly, I believe that 2 tracks are "reserved for CP/M" even
though it is in ROM and not stored on disk.
It was not uncommon for CP/M disks to have "reserved" or "system"
tracks,
even when the particular disk was not a bootable "system" disk.
I don't remember for sure, and don't have convenient access to my
materials, but 16 256 byte physical sectors makes sense.
The drive manual
http://electrickery.xs4all.nl/comp/px8/doc/PF-10Manual.pdf
SAYS 9 512 byte sectors, but that seems likely to be in error from a cut
and paste boilerplate from a different machine, because the more specific
information is all for "64 sectors", which means CP/M RECORDS or "logical
sectors" of 128 bytes each. THAT would be consistent with either 8 512
byte PHYSICAL sectors, or 16 256 byte PHYSICAL sectors.
--
Grumpy Ol' Fred cisin at xenosoft.com
17 Dec
17 Dec
9:16 a.m.
On 12/16/2018 11:56 PM, Fred Cisin via cctalk wrote:
Standard SSSD 8" that is the case the fist two tracks are for
"system"
and the system is loaded from those.
Most other do a variation depending on format and space.? CP/M ( the
modules CCP, BDOS, BIOS) fits in about 8k
so that defines the size of system tracks.?
CP/M revolves around logical sectors of 128 bytes so anything larger
2556/512/1k requires
blocking and deblocking in the bios.
> On December 16, 2018 at 11:14 PM allison via
cctalk
> <cctalk at classiccmp.org> wrote:
>>
>>> On Sun, 16 Dec 2018, Norbert Kehrer via cctalk wrote:
>>>> I have not tested it, but I suppose, that also the PX-8 and PX-4 used
>>>> the protocol,
>>>> because the protocol specification defines the following device
>>>> numbers:
>>>> - HX-20: 0x20 (probably also used for the HC-20)
>>>> - PX-8:? 0x22
>>>> - PX-4:? 0x23
>>>
>>>
>>>
>> PX-8!
>>
> A subject dear to me.? I still have the px-8 I bought new (borrowed
> the money from my sister) as a young man in 1984.? Alas, I could
> never afford the PF-10 disk drive.
>
I've had one for many decades and 2 more for well, now its two decades.
Handy little critter and they do see use.
>> However, the PX-8 3.5" had 40 cylinders, with 67.5 tpi, instead of the
>> common 80 cylinder 135 tpi of other 3.5" disks.
>> Those 40 cylinder 3.5" drives are quite rare.
On Sun, 16 Dec 2018, Will Cooke via cctalk wrote:
Somewhere in my searches I recall reading that
the 3 1/2" drives used
the same format as the 5 1/4" ones.? Maybe 40 tracks of 16 256 byte
sectors.? Oddly, I believe that 2 tracks are "reserved for CP/M" even
though it is in ROM and not stored on disk.
It was not uncommon for CP/M disks to have "reserved" or "system"
tracks, even when the particular disk was not a bootable "system" disk.
I don't remember for sure, and don't have
convenient access to my
materials, but 16 256 byte physical sectors makes sense.
Yes, it would be enough.? Save for the PX8 has CP/M loaded into ROM so
the system tracks are largely wasted.
I believe there is some drive and system level configuration information
there but we are talking less than
a sector or two.
The drive manual
http://electrickery.xs4all.nl/comp/px8/doc/PF-10Manual.pdf
SAYS 9 512 byte sectors, but that seems likely to be in error from a
cut and paste boilerplate from a different machine, because the more
specific information is all for "64 sectors", which means CP/M RECORDS
or "logical sectors" of 128 bytes each.? THAT would be consistent with
either 8 512 byte PHYSICAL sectors, or 16 256 byte PHYSICAL sectors.
It seems that way as it matches the PF-20 5.25" drive.? However the
format on the drive also seems consistent at 9x512.
Its not uncommon to use the whole system track or two even if it has
"excess" space. Often the first sector contains the full
disk book rather than a minimal 1 sector boot.? There is a lot of
latitude and mostly why copy format programs such as yours
existed due to same drive and media and many many different formats.
I've gotten away from rotating media on a few of my CP/M systems and
they go to the edge of what CP/M permits
as in EPROM loaded, ROMdisks, RAMdisks and CF.
Allison
9:23 a.m.
On 12/16/2018 11:39 PM, Will Cooke via cctalk wrote:
Here is one I am familiar with that runs on Linux.
Only does drives, AFAIK, no display.
https://fjkraan.home.xs4all.nl/comp/px4/vfloppy/ Thats true, but the IO on the PX-8
allows for redirection to the serial
port for console and even keyboard.
I've many times used it with my VT320 to save my poor eyes.
On December 16, 2018 at 11:14 PM allison via cctalk <cctalk at classiccmp.org>
wrote:
A subject dear to me. I still have the px-8 I bought new (borrowed the money from
my sister) as a young man in 1984. Alas, I could never afford the PF-10 disk drive.
The system in the base PX-8 has a system area for user patches. the
drive table is part of the BIOS and
there are provisions for intercepting the calls to there and patching in
changes or extensions.? Its
detailed in the manuals.
On Sun,
16 Dec 2018, Norbert Kehrer via cctalk wrote:
PX-8!
I have not tested it, but I suppose, that also
the PX-8 and PX-4 used
the protocol,
because the protocol specification defines the following device numbers:
- HX-20: 0x20 (probably also used for the HC-20)
- PX-8:? 0x22
- PX-4:? 0x23
> However, the PX-8 3.5" had 40 cylinders,
with 67.5 tpi, instead of the
> common 80 cylinder 135 tpi of other 3.5" disks.
> Those 40 cylinder 3.5" drives are quite rare.
Somewhere in my searches I
recall reading that the 3 1/2" drives used the same format as the 5 1/4" ones.
Maybe 40 tracks of 16 256 byte sectors. Oddly, I believe that 2 tracks are "reserved
for CP/M" even though it is in ROM and not stored on disk.
ceramic magnet lost its stuff over time.? When I
have time the next
project will be a Atmega2650 running
a CF to via serial interface.? The drive table can be patched for a
larger (up to 8mb) drive.
I've been planning something very similar for a
while, but using an Arduino (ATMega 328) or bare AVR chip and probably a smaller/simpler
flash chip. I din't know about the drive table. That's interesting. Would a new
ROM have to be burned with the new table? Do you have an links to the info? With appropriate format handling software on the PC,
it should be
possible for a PC connected using your system to work with actual
Epson diskettes, and emulate the Epson external drives.
There are several software packages on the net to do the fake of the
disk via serial and manuals of the system to
explain the format.? Likely that software could do the earlier HX20 (and
friends) with minor tweaks. And if anyone is interested here are some more links:
http://oldcomputer.info/8bit/hx20/index.htm#links
Navigating through some of those links takes you to the protocol:
https://fjkraan.home.xs4all.nl/comp/hx20/epsp.html
Note at the bottom of the page it says the PX-8 and CP/M only use four of the functions.
This link has lots of HX-20 info.
http://electrickery.xs4all.nl/comp/hx20/doc/index.html
The tms files near the bottom (ch 10-11?) describe the protocol and how it functions in
detail.
Will
?Indeed.? its all there.
24 Dec
24 Dec
3:42 a.m.
I now also added graphics support to flashx20.
The commands to draw dots and lines available in Epson BASIC can now be
used to create high-resolution pictures in different resolutions and up
to 8 colors on the screen of the Windows PC connected to the HX-20. The
graphics screen is shown in a separate window, so that the text display
still remains visible in the console.
The new version can be downloaded as a zip file containing the
"flashx20" program for Windows computers, some BASIC examples and
graphics demos, and the user manual as a pdf file. You can find some
screenshots and the download at http://members.aon.at/nkehrer/
Merry Christmas!
Norbert
2037
days inactive
2046
days old
10 comments
5 participants
participants (5)
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allisonportable＠gmail.com -
cisin＠xenosoft.com -
norbert_kehrer＠yahoo.de -
silent700＠gmail.com -
wrcooke＠wrcooke.net