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The Answer Guy

By James T. Dennis, tag@lists.linuxgazette.net
Starshine Technical Services, http://www.starshine.org/

(?)tv cards and dual monitor

From Desperado on 27 May 1998


Did you hear about TV cards in LInux? am I dreaming?

(!) I've heard about them. However, I don't have one to play with and I haven't even found a decent HOWTO or website to explain what's required and what's broken (if anything). [At press time, the Hardware Compatability HOWTO section 22.5 mentions some programs that support several TV tuner cards. It's mostly pointers to tgz files, though, not real help with setup. -- Heather]

(?) What about dual monitors? In WIndows 98 it needs at least a PCI bus, but what about 486 users? I found something relative for Linux (multimon or something like that) but It works with a black and white video card (don't remember exactly), anything to work with two monitor in Linux, using two ISA video cards?

(!) As I've explained before, the classic situation with PC and multiple monitors used to be that the you couldn't put two VGA (actually any combination of two VGA/EGA) cards into the same system. Thus you could put a monochrome video card (text only or "Hercules" MGA) into a system to co-exist with a VGA or EGA. Frankly I don't remember where CGA was in this mess, though I could look it up if I really cared. I personally never used CGA --- it was just the worst of all worlds.

The 'multimon' patches for the Linux kernel are very old -- and probably haven't been updated to the 2.0.x (much less the 2.1.x) kernels. I've never used them. I seem to recall that it only applied to using a system with one VGA (or EGA?) card and one "Hercules" MGA (monochrome graphics adapter) or possibly an old MDA (text only monochrome display adapter --- the original IBM video card).

Another approach that used to be possible was to use very specialized adapters like the old TIGA (Texas Instruments Graphics Array?) or DGA (?) cards. These were high resolution graphics adapters that cost thousands of dollars and weren't compatible with VGA or any other "standard" cards or software.

However I've never heard of Linux (XFree86) drivers for TIGA or DGA cards --- and I'm not sure if they are still in production. In fact I don't actually know anything about these old beasts --- I just vaguely remember some discussions I had with other nerds back in the late 80's where the subject came up.

When I last discussed this in LG (many moons ago) I didn't know that some of the modern PCI video cards had the option to be used in a "non-VGA" mode. Thus you can take some PCI video cards configure them to co-exist in a system with another VGA video card. I have heard that some of the commercial X servers support multiple physical displays on some cards. I don't seem to recall any of them for XFree86 --- but a search of their web pages:
...would provide a far more definitive answer.

The last I read none of the XFree86 servers support multi-headed operation. This is from the following entry in their FAQ:
I have yet to see anyone using this feature. One of these days I might try it. However, not this month.

The Commercial vendors to check with would be:
Xi Graphics (formerly X Inside):
... and:
(there may be others but these are the two that I think of when I think of the commercial X servers for Linux).

BTW: Metrolink didn't appear to have any online FAQ or web site search engine. However Xi's FAQ lists a sample configuration for use with two Matrox Millenium cards at http://www.xig.com/support/faqs.servers.html#Anchor-a5

(?) What is inetd? when I am trying to install the ftp rpm, I get the message "you need inetd", but in my Red Hat 5.0 CD, in the RPMS directory there is nothing similar to that name.

(!) That sounds wrong to me. I would expect that message from the ftpd (the FTP Server package). The default ftp client should be a part of the NetKit package (probably in the base RPM).

'inetd' is a IP service dispatcher. It listens to a list of TCP/UDP ports and dynamically launches programs as connections are requested for the corresponding "well known services" The mapping of ports to services is done via the /etc/services file, and the mapping of programs (daemons) to services that will be managed by inetd is in /etc/inetd.conf.

In all of the major Linux distributions most of the the inetd services are configured to run tcpd (TCP Wrappers). This utility will check the the IP address of the client that is making the connection request against one or two lists of rules (/etc/hosts.allow and /etc/hosts.deny). 'tcpd' also makes some sanity checks, for example to see if the client's reverse mapping (a DNS request --- gethostbyaddr() actually --- matches one of the addresses that's returned by a forward mapping (gethostbyname). That's called a "double reverse lookup" and is somewhat more difficult for an attacker to "spoof" than just a reverse (in-addr.arpa) entry.

Are you trying to use an ftp client or a server (daemon)? You might also try ncftp (Mike Gleason?) which is a nice curses mode (full screen) client. You can also try lftp which has some nice scripting features. In fact ncftp also has some rather handy features for use in scripts.

Another option is to use mc's (midnight commander) ftp features. To do that just load the program and type cd ftp://..... (the URL form of the ftp site's name).

Shortly thereafter you should see the files and directories from your FTP site appear in one of mc's navigation panels --- you can than navigate the other site, tagging, copying, and managing the remote files as though there were in a local directory tree.

(?) One thing more, what about download managers? I use Get Right, but there is no version for Linux, well there is no Java Runtime Environment for Linux. Any other good application for that?

(!) I presume you mean that you'd like to select a number of files in an ftp client and have the system continue to try downloading ('get'-ting) them until they are all successfully retrieved. Perhaps you'd even like to just tag the files and defer the actual download until later (say, late at night when there's just less bandwidth in use all over the 'net).

I think there are many programs that can do this. I've used 'mirror' (Lee McLoughlin's Perl script) many times --- but that is more of a programming utility and it has no interactive front end. The best bet would be to search the Linux Software Map (http://www.ssc.com/linux/apps.html) with the words "ftp" and "client"

I suppose it would be nice to have an FTP client that had an option write all your file selections to a file and execute the fetch later as an 'at' job. Perhaps one of our readers will know of one.

Also there is quite a bit of Java support for Linux. I don't know about the JRE specifically but it appears to be supported according to the canonical Linux/Java site (http://www.blackdown.org):
Java-Linux: Javasoft(TM) Products

(?) Thank you for your help.

(!) I hope that helps. Look at the Blackdown.org site for more info about Java under Linux.

Copyright © 1998, James T. Dennis
Published in Linux Gazette Issue 30 July 1998

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