The Answer Guy

Combining modems for more speed

Thanks for reading this post. I have heard that it's possible to set up Linux to combine two analog modems into one so as to double the speed of a connection. Is this true, how does this work and where can I get more info, guidance, how-to, etc.? I have Slackware 96 from Infomagic. Your truly, Keith Bell

I've heard of this as well. I've never used it but let's look it up...

Ahh... that would be the EQL option in the kernel. Here's an excerpt from the 'make menuconfig' help pages (in the 2.0.27 kernel sources):

Linux Kernel v2.0.27 Configuration

EQL (serial line load balancing) support:
If you have two serial connections to some other computer (this usually requires two modems and two telephone lines) and you use SLIP (= the protocol for sending internet traffic over telephone lines) or PPP (= a better SLIP) on them, you can make them behave has to be supported at the other end as well, either with a similar EQL Linux driver or with a Livingston Portmaster 2e. Say Yes if you want this and read drivers/net/README.eql.

So that file is :
EQL Driver: Serial IP Load Balancing HOWTO
Simon "Guru Aleph-Null" Janes, simon@ncm.com
v1.1, February 27, 1995

(After reading this you'll know about as much on this subject as I do -- after using any of this you'll know *much* more).

Dialup Problem

I don't know if you can, or even are willing, help me witha problem i have. I'm running redhat 4.0, on a p120 w/24 megs of ram, kernel 2.0.18

I'm willing.

When i try to dial my isp, i get logged in fine, but its REALLY slow. i'm using the 'network module' ppp thing in control panel on X. mru=1500, asyncmap=0,speed=115000, i couldn't find a place to insert mtu, and when i tried putting that in /etc/ppp/options the script this program was using wouldn't work.

Usually I see these symptoms when there is an IRQ conflict. Some of the data gets through -- with lots of errors and lots of retransmits but any activity on the rest of the machine -- or even just sitting there -- and you get really bad throughput and very unreliable connections.

I would do all of your troubleshooting from outside of X. Just use the virtual consoles until everything else works right. (Fewer layers of things to conflict with one another).

Take a really thorough look at the hardware settings for everything in the machine. Make a list of all the cards and interfaces -- go through the docs for each one and map out which ones are using which interfaces.

I ended up going through several combinations of video cards and I/O cards before I got my main system all integrated. Luckily newer systems are getting better (this is a 386DX33 with 32Mb of RAM and a 2Mb video cards -- two IDE's, two floppy drives, two SCSI hardisks, an internal CD-ROM, and external magneto optical drive, a serial mouse, a modem (used for dial-in dial-out, uucp, and ppp) and null modem (I hook a laptop to it as a terminal for my wife) and an ethernet card.

Another thing to check is the cabling between your serial connector and your modem. If you're configured for XON/XOFF you're in trouble. If you're configured for hardware flow control and you don't have the appropriate wires in your cable than you're in worse trouble.

Troubleshooting of this sort really is best done over voice or in person. There are too many steps to the troubleshooting and testing to do effectively via e-mail.

File Referencing

> "A month of sundays ago L.U.S.T List wrote:"
>> 	1. I do not know why on Linux some program could not run
>> 	correctly.
>> 		for example
>> 	#include 
>> 	main()
>> 	{
>> 		printf("test\n");
>> 		fflush(stdout);
>> 	}
>> 	They will not echo what I print.
> 
> Oh yes it will. I bet you named the executable "test" ... :-)
> (this is a UNIX faq).
> 

I really suggest that people learn the tao of "./"

This is easy -- any time you mean to refer to any file in the current directory precede it with "./" -- this forces all common Unix shells to refer to the file in THIS directory. It solves all the problems with files that start with dashes and it allows you to remove :.: from your path (which *all* sysadmins should do right NOW).

That is the tao of "./" -- the two keystrokes that can save you many hours of grief and maybe save your whole filesystem too.

WWW Server?

Where can I get (or buy) a WWW server for LINUX?
Please, help me.

Web servers are included with most distributions of Linux. The most popular one right now is called Apache. You can look on your CD's (if you bought a set) or you can point a web client (browser) at http://www.apache.org for more information and for an opportunity to download a copy.

There are several others available -- however Apache is the most well known -- so it will be the best for you to start with. It is also widely considered to offer the best performance and feature set (of course that is a matter of considerable controversy among "connosieurs" just as is the ongoing debate about 'vi' vs. 'emacs').

You're welcome.