Something to share as an aside. for individuals using command line Linux, the issue would be a problem too. Not only do hardware synthesizers like the one I use need the ports, but so do braille embossers, printers that allow individuals who read and print braille for personal, and commercial use. I will add that some who embody a print disability whouse speech, that includes say reading experiences, can read with their ears at 500 words a minute or more. That kind of lag would put USB adapters off the table. Encountered a thread on the Linux list for speakup making that point recently. Kare On Tue, 1 Aug 2023, Anthony de Boer via talk wrote:

On 8/1/23 00:02, D. Hugh Redelmeier via talk wrote:

...

... I guess that a USB-to-serial dongle would be OK.

The FTDI USB-Serial adapters were very good, but then the market got flooded with cheap PL2303-based ones that are horrible, losing whole swathes of text during fast screen updates. They're generally only okay for slow traffic.

I haven't had to buy another one in several years so haven't sampled the market recently.

Anthony

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Hi, My understanding from those who use USB to serial adapters is the speech lag with missing text is quite profound. With my ears I read at around 375 400 words per minute, so..I imagine my best bet will be continuing to have my machines custom built. speaking of which, while property standards has no authority to review how hydro is flowing in my apartment, the electrical safety authority who 311 Toronto connected me with, just might. Getting an inspection on Tuesday. Kare On Wed, 2 Aug 2023, D. Hugh Redelmeier via talk wrote:

Parallel ports disappeared first. Serial later.

Real PC parallel ports were repurposed for all kinds of hacks. Those might not work with USB dongles. But just using them for printers (and things that look like them to the interface) should work fine with USB dongles.

How fast do you need your serial port? I imagine that USB dongles should work.

DOS on bare hardware is getting slightly tricky. New computers have UEFI firmware instead of BIOS. Many, but not all, can boot as if they use BIOS, using a module in the firmware called CSM. Enabling the CSM and MBR booting are usually settings in the firmware setup page.

With some skill and knowledge, you might be able to run DOS in a virtual machine, even with USB devices. I'm not sure because I've never done it.

Annecdote: a friend has an old printer (HP LaserJet 4mp) that he connects via a parallel port USB dongle. This worked fine in Windows 10. Windows 11 does not support printers connected by parallel ports. But Linux supports his printer. He want to run Ubuntu under Window 11's Windows Subsystem for Linux, and in that Linux virtual machine, run the printer and make a print server available to Windows. I don't know if he has succeeded.

Best guess on what you can use:

- if USB dongles work for your applications, most computers can likely be made to work. Not the thinnest and lightest and latest laptops.

- good solid off-lease workhorses might be a better choice because the improvements since then are probably not useful to you.

- this advice probably applies for both notebooks and desktops.

Note: my guesses about your needs have been hit and miss. --- Post to this mailing list talk@gtalug.org Unsubscribe from this mailing list https://gtalug.org/mailman/listinfo/talk

On 8/2/23 03:31, D. Hugh Redelmeier via talk wrote:

| From: Anthony de Boer via talk <talk@gtalug.org>

| The FTDI USB-Serial adapters were very good, but then the market got flooded | with cheap PL2303-based ones that are horrible, losing whole swathes of text | during fast screen updates. They're generally only okay for slow traffic.

What does that mean exactly? The serial-to-USB dongles are not connected to the screen so "fast screen updates" isn't exactly a dongle function.

Are you saying that they get over-run during fast or sustained transmission? That sounds like a driver problem.

The usual situation was using the dongle in the serial port of a device that was about to start up and output several kilobytes of boot messages to its serial console at 57600 baud, using minicom in an xterm on my Linux workstation and the USB-Serial dongle to watch what was happening, and realizing chunks were missing from the story the device was trying to tell me. I think that if it was a driver problem our Linux community would have jumped on it, especially for something as ubiquitous as the PL2303, and when I looked into it the news was that it was a chip problem.

Even in the old days, overrun was too easy with some serial input ports. Original UARTs were double buffered. 8250's like in the original PC had deeper buffers. If you don't have deeper buffers, you need the OS to have very quick real-time response to serial port interrupts.

Old-timer stories -- feel free to ignore:

My Kaypro II could handle 9600 terminal emulation only because I rewrote parts of the firmware (CP/M BIOS in EPROM) for faster screen output and wrote my own terminal emulator to use serial port interrupts.

The NABU 1600 could handle 9600 serial input only because Sheila Crossey of HCR wrote some code in the UNIX kernel to handle serial input in a pseudo-DMA way.

I think I've still got a Kaypro II somewhere because I just can't stand to e-waste such great engineering of yesteryear, especially after spending quality time with it back then. The closest I got to the serial ports was writing an xmodem for CP/M to try and juice a bit more transfer speed out of our hardware, and later porting that to early MSDOS. That would have been nearly the last assembler I wrote before gaining access to the new C compilers that were starting to appear. A bit later we had Unix servers with dozens of users on serial ports all talking to a single-core 386 or 68k and we thought these was a good systems. A big part of it was smart multi-port serial cards that handled "cooked-mode" line buffering for the users and only interrupted the OS when there was a whole line of input to process. That would have been mid-80s into the early 90s. Anthony