Copying files from old DOS to Win10

[David Wade]

There used to be "mini kermits" in Basic that you could transfer as text...

Dave

[John Rumm]

and probably 90kB of storage on each :-)

I remember a certain feeling of buyers regret having splashed out for a storage caddy that held 10x 5.25" floppies. I thought I might have wasted my money since I could not imagine ever filling it up!

[The Natural Philosopher]

So? My pint is that if he has compatible drives and a machine, why involve the 1512 at all?

[Dave Plowman (News]

I recently bought a new ATX MB. It still had a serial port on the MB - but a Molex. Needed an adaptor to bring it out to the back panel as a DB9. But didn't use up a PCIe slot.

Does anything still use parallel ports, other than old equipment?

[tabbypurr]

400k each, so 0.8M disc space for the whole network.

lol

[NY]

I bought my first computer, a Transam Wren (CP/M 3), in 1981.

I decided I could afford the upgrade from 16 KB to 256 KB RAM, but the optional 5 MB hard drive was just too expensive. I think the whole computer cost about £1000 (1981 prices).

It was an all-in-one design, similar to a laptop in that the one box contained keyboard, 2x 360 KB 5 1/4" floppies, 9" amber (monochrome) screen, CPU/RAM and PSU. Oh, and a 1200/75 baud modem. It was bloody heavy - the above site says 12 kg.

It came with an office suite: Perfect Writer/Calc/Filer which was not WYSIWYG, so you had to embed formatting codes and hope that the printed document was formatted as you wanted.

But it worked. I used it for writing my final-year project report at university, printing to an Epson FX80 9-pin matrix printer, and I bought Turbo Pascal which allowed me to write programs that ran a lot faster than the BBC Basic that was supplied.

I later found some software (22DISK, probably) which could read the data floppies on a DOS PC, so I was able to extract the files and preserve them on something a bit more long-lasting (and widely-readable) than a non-DOS-format floppy.

The Wren came with an interface socket for an external hard disc, so I built myself an analogue-to-digital board and a digital-to-analogue board that used that port to read/write. There was also a DIN socket for RGB monitor, so I built myself a PAL encoder that could drive a TV with BNC or SCART for colour composite video, and a simple resistor matrix to derive a luminance signal for a sharper but monochrome image.

It still worked until a couple of year ago when I tried it and there was no power to anywhere - and its PSU was proprietary and I couldn't find a replacement, so it went to the tip.

[Bob Eager]

I bought an Advance 86B in 1984. It too came with the Perfect suite.

The Writer (and indeed Calc) used Emacs default keystrokes.

Which is why, to this day, I use Emacs (and ed).

[John Rumm]

Huh?

(I think your attributions are a bit cocked up)

The 1512 is the old dos machine he wants to get files from, and it has

5.25" drives, and a HDD that would be non trivial to mount in modern machine.

[John Rumm]

Yup one com port as a header is still quite common IME.

old and perhaps specialist stuff like lab or process control kit.

[Grumps]

Well it nearly works. I made a cable, DB25 to DB9 with the following pinout:

PC1512 Modern 2 TX RX 2 3 RX TX 3 4 RTS CTS 8 5 CTS RTS 7 6 DSR DTR 4 7 GND GND 5 20 DTR DSR 6

I can transfer text files just using "copy com1 file.txt" etc, and I can nearly transfer binaries using copy /b - except it screws up part of the way through at no particular point - about 5-6k in.

The PC1512 doesn't have mode.com so I'm changing com settings using ll3 (laplink).

When running laplink in dosbox on the modern PC (i7-6700k, mini-itx - so no room to add PCIe cards, and I'm using a Prolific USB to RS232 cable), dosbox becomes less responsive and I get RX overrun errors. Laplink nearly works - on the PC1512 it shows the remote drive contents.

So, nearly but not quite. Any thoughts on above? Get a different USB to RS232 cable (not Prolific based)?

I've checked ALL other PCs (5) and laptops (4) here and NONE have a serial port!

The PC1512 does have a C compiler and masm, so I might have to go that route and write something myself. Ah, sod it - no text editor. That leaves debug.com.

[Andy Burns]

either lack of flow control, or embedded EOF (ctrl-Z) characters in binary files.

edlin?

[Grumps]

Nope.

Surely a ctrl-Z in a binary file should not upset things if you're doing a binary copy?

But... One of my old unused PCs has a serial port header, so... Plugged in and now laplink connects to the old PC1512 and works like a charm.

Was it worth it I ask.

[John Rumm]

The PC BIOS serial port routines are notoriously unreliable since they are polled and not interrupt driven. So while device style copies from the command line like that work in theory, practice is a whole different ball game!

(I recall offering (a long time ago ~1988) to knock up a quick utility for someone to display the content of a binary serial data stream on screen of a PC for debug / logging purposes. I learnt to my cost that just opening the reading the com port device as a file in turbo pascal did not work reliably and ended up having to drive to the trials site on Salisbury plain MoD test site to go fix it! Soon found I had to ditch all the BIOS int 14h code, and write my own interrupt handler for reliable reception)

With laplink you only normally need mode on a remote machine that does not have laplink, then you can use it followed by a CTTY instruction to receive the stub loaded.

Prolific ones are supposed to be good - although there are a huge number of ripoffs/clones about its hard to know what you actually have. So yup worth trying others.

Check the options for selecting serial ports in dosbox.

Might also be worth trying VirtualBox (Oracle) on the new PC instead.

On the outside, or the motherboard? (many have the pinout on the motherboard, but lack the cable and connector to bring it to the case)

What version of DOS is it running?

(not even edlin?)

[Grumps]

It has WordStar!

So, dosbox on my i7 PC didn't work well enough. Rx overrun errors.

And after I found one of my old PCs did have an RS232 header on the motherbaord, I found that dosbox on that PC (Win98) nearly worked except the PC1512 laplink showed the remote folder structure as essentially garbage!

But... Booting that Win98 PC straight to DOS and then running laplink worked flawlessly.

I now have all of the PC1512 files retrieved and am wondering whether it was really worth the effort.

[Paul]

The USB to serial adapters have decent-sized buffers in them (bigger than a 16550), such that you should not lose characters. You need to have RTS/CTS (HW) or XON-XOFF (SW) for flow control, to make it all play nice. I still find, with at least one USB dongle in the path, it isn't as smooth as it could be.

And your wiring plan is probably intended to be a "null modem cable", as you can't get two PCs to talk to one another, unless the wires are flipped. I have a cable right now, between the two PCs, and there is a null modem adapter in the stack of adapter plugs in the cabling chain. And like the example here, it has "Null Modem" written in the plastic.

Usually the USB ones with the 9 pin connector, have "full" interfaces on them. If you buy a USB to TTL level four wire serial port, those only have TX,RX,GND,+5 on them, so no hardware flow control. You could try XON/XOFF in that case (I don't know how binary transmission works in that case though). With proper RTS/CTS, the data path should be fully eight bit transparent. Especially if you set the mode to 8N1 and not 7N1 or something :-) You can still break it, using settings.

Paul

[Andy Burns]

you could check by doing a copy /b con com1 at one end, and copy /b com1 file.ext

at the other end then typing stuff, including a ctrl-z

[jrwalliker]

This one has RTS and CTS on the pin header. The other modem signals are available on pads that do not have pins fitted as standard.

John

[John Rumm]

Oh yeah, that will do it! CTRL K rules!

Well better now and not need them, than some point in the future and finding that they are irretrievable :-)

[John Rumm]

There are quite a few additional layers of software in the setup here though. Laplink etc will be banging (what it thinks is) the UART hardware directly - which is fine under real DOS, and still ok under Win95 style hardware virtualisation. However now you are translating that up though a VM hypervisor, and VM host, Presumably some glue code to migrate IO out of the VM to the "real" com hardware, and then on the host that is mapped back into USB driver stack. In some ways it surprising it works at all.

(not even sure if laplink of that era could take advantage of the fifo of the 16450/16550 if it still thinks the hardware is an 8250 UART)