Date: Wed, 15 Oct 2014 20:35:08 -0500 From: "Martin G. McCormick" <martin@server1.shellworld.net> To: questions@freebsd.org Subject: Re: FreeBSD and accessibility Message-ID: <20141016013508.A26EF228B7@server1.shellworld.net>
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This particular thread is a month old so I apologize in advance as that is a long time in discussion list years, so to speak. I am blind, also and have been using unix for a bit over 25 years. I had gotten a little behind on following the FreeBSD list but this discussion warrants some further input. The unix-like operating systems are a model of accessibility when compared with other well-known OS's. To tap in to all this usefulness, however, one needs a way in and that can be a problem at times. until about 6 years ago, I used a P.C. running MSDOS, a special box which was a hardware-based speech synthesizer and the MSKermit application which is an excellent terminal emulator as well as a file-transfer protocol. If a unix system had a serial tty port, one could configure that port to be a login console and then all you needed to make your system in to a talking terminal in to the unix system was a null-modem serial cable or to have the unix system connected to a modem or serial concentrator. One could run that unix system to one's heart's content via a serial console port. As for installations of FreeBSD on to a new system, One could make that fully accessible by re-burning the installation CD after modifying a small file in the /boot directory of the installation CD so that it now comes up accessing both the local screen or video display as well as any RS-232 ports on the target system that you designate as a serial console. You then hear or read in Braille everything sent to the local video display. You can answer the prompts and do your work just fine as long as you are running the correct terminal emulation on your talking system. The basic idea is that the target system doesn't need to know anything about speech or Braille but it definitely does need to have this serial console port enabled or it is just another sealed up system that you won't be able to do anything with. In modern times, RS-232 ports are becoming scarce so getting in to an installation to remotely access it is becoming a problem again. This is where things are becoming frustrating once again. I need to install FreeBSD 9.1 right now on a brand new system since it is a replacement for an older system that may be failing. I have discovered that it seems nigh impossible to re-build the FreeBSD installation disks due to some problem with tar and the extraction process. I originally was going to use the FreeBSD memstick image and install via a thumb drive but the new system appears to not boot from the thumb drive even though it sees it according to a sighted coworker who hooked up a monitor and watched it ignore the usb drive. I tried first a modified memstick image and then tried the straight memstick image with no mods at all to see if maybe I was killing it's bootability. That system just refuses to even start to boot. So basically, you should be able to make a FreeBSD installation accessible to either speech or Braille by virtue of it's being unix-like and thus blessed with standard input and output. The problems I am having right now will probably eventually be solved but Ah, for the good old days when one could just get tar to do what it is supposed to do and not produce an image file twice as large as it should. For those not familiar with what I am referring to, look at recent discussion archives and postings from me about this problem. A great solution would also be a MFS-based method to communicate over a network with the installer-- anythingbesides just the video output display. Polytropon writes: > On Tue, 16 Sep 2014 11:14:29 -0400, Littlefield, Tyler wrote: > > I'm not sure how this is supposed to work. The braille readouts > > you speak of are called braille displays. > > I'm also not entirely sure how they worked, but I can > imagine the following way: > > The text output on the screen is directly correlated > with a specific region in the RAM. If I remember > correctly, that is 0x8800 for color screens (VGA, > EGA, CGA) and 0x8000 for b/w screens (MDA, "Hercules"). > The regions are 4000 bytes in size: 80x25 characters > are 2000 bytes text, plus another 2000 bytes color > (one byte to hold background, foreground, attributes). > So a TSR was installed to "scan" that memory region > and transfer the character information (and stripping > color information) via serial port to the Braille display > which would then output it. Having _that_ kind of access > to the screen content is quite easy. I know because I > once wrote a program that copied the text of the color > screen to the b/w screen. In Pascal. Real programmers > don't use Pascal, but I was young and stupid. :-) Whatever works! I used 8086-based assembler to write functionally similar code to push at that hardware-based speech synthesizer. Trust me. We don't need to go there these days. We just need to make the good things that are available now work and fortunately, they usually do. Most of the FreeBSD systems I have set up do not have sound cards and are up to 150 miles away when in their proper operating location so what you want is what is called a headless installation. Martin
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