System Administration

Roff, Groff, and the Roots of Computer Typesetting

Today we take it for granted that computers can set type, but from the 60s to the 80s, most computers used either teletypes or character-based screens. The Xerox Star and Apple Lisa and Apple Macs, and PostScript changed this, but before them, typesetting was done using weird command languages that would send pages to special typesetters. The most well known setup was troff, which lives on in groff and in Solaris. The troff system used a computer typesetter called a CAT, and it wasn't a bitmap laser printer. It has these fonts that were spools of film that were photographs of letters. The font sizes were created by projecting the image of the letter onto the page at different sizes. I believe the rest of the process was like a photocopier - the toner goes on, and then is transferred to the paper, and fused.

Does software get old and wear out?

This isn't addressed to anyone in particular, but it's a common question: does software get old and wear out. They ask because their computers have gotten slower, or features have stopped working.

Sysadmin Notebook

This is a collection of articles about system administration of Windows, Unix/Linux/BSD, and Macintosh computers and networks.

Checklist of things to do Before Purchasing a SSL Certificate

A short list of things to make purchasing an SSL cert easier.

1. Check your domain registration and make sure the Registrant and Administrative Contact will match the party that will purchase the SSL cert. Just to be safe, make sure the address matches the billing address of the credit card you will use. Changes may take a while, and may require email verification.

2. Decide on which domain name you want to associate with the cert.

3. In the DNS, make sure the IP address of the server matches the domain. Changes may take a day to propagage.

Generate a Page of Random Passwords with Javascript

The attached HTML page is a password generator that creates a page of random 10-character passwords. It helps you manage one password per website, so a password leaked for one site doesn't get used on other sites. To use it, click and view the file.

Mass Convert IP Addresses to Domain Names with a Filter

A PHP script to convert many IP addresses to domain names.

Preserving Your Users' Privacy

If you operate a website, or wish to retain privacy while visiting websites, you need to be aware of how websites share their traffic data with other sites.

What Kind of Monitor Should You Use? sRGB, Adobe RGB, the new wider Adobe RGB, or what?

I was looking for monitors and got into the whole color thing. Here's my summary of findings.

It's All Beeps: How a PBX Works with a Voicemail (VMX) System

I'm reading an Avaya (Lucent) manual about Avaya and Duvoice DV2000 integration. Being a phone novice, I don't really grasp how these technologies integrated. I assumed there was some kind of computer network between the voicemail and pbx.

That assumption was totally wrong.

Search and Replace in a MySQL Database after Moving a Site with WGET

Sometimes you need to move your old website off of a CMS, or at least archive it, and the only way is to use WGET to mirror the website. Wget downloads entire websites, turning dynamic sites into static sites. The following command would download the site

wget -H, '--restrict-file-name=windows' -A gif,jpg,html,tcl -np --convert-links --html-extension -rx

Building Computers from Parts Rocks

I was just thinking about computers I've owned, and six came out of boxes, ready to run. An Atari 800, and Atari 1040 ST, a Mac Quadra 660 (I think), a Mac iBook, a Mini Mac, and a Compaq budget PC. The rest were bought used, found in the trash, built from parts, or were kits or kit-like (barebones kits that took disks). I'm not sure how many computers I've owned, total. Probably between 20 and 30.

Terminal And Serial Port Tips

[This article is obsolete, but the serial cable is not, as it turned out. For more info, read about the Yost cable standard.]

Bash Shell Scripting Cheat Sheet

It's like a dos bat file, but with nifty little features, like actual looping constructs and the ability to mess with program output creatively. For a long time, a large fraction of the net's information infrastructure was programmed using shell scripts. The internet worm of 89 used them. Today, skript kiddies use "hack scripts" that are shell scripts that emit C code, compile it, perform the hack, and then clean up after themselves.

Here's a quick cheatsheet. Each line is a valid line in a program.

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