About A.P. Lawrence

A.P. Lawrence provides SCO Unix and Linux consulting services http://www.pcunix.com
Security Through Obscurity Threatened as Macs Become More Popular?

At Apple’s in the eye of flaw finders, Mac users are warned that the growing popularity of the platform will attract viruses and security hacks.

Perl ‘Eval’ for Data Validation

I recently did a little web based Service Schedule. This is something that gets its data from another program: in other words, the details of what will be serviced and when are supplied by that program; this web based app validates things, assigns technicians and does some other things that the first program doesn’t.

Vanderpool, Intel Dual Core VT and Intel Macs

I (and a few others) been blabbering about this for a while but it seems that very few people are really aware of what is about to happen here.

C Pointer Problems

This was written in January of 1990, but is still meaningful today, though we do have better debugging tools now. This was originally published in the Boston Computer Society’s PC Report.

Rounding Time

It was a long, hard day. Up early to clean a room of furniture so that new carpet can be put in later this week, off to a real estate refinancing closing after that, back to rake leaves and then the usual computer type work.

Terabyte, Tebibye

At Will dead media ever end? I opined that we are getting closer to the point where it is unnecessary to have more storage space.

Fedora Time Bug

The question of setting time comes up frequently. Setting the timezone and the system clock can be confusing, particularly if the machine is dual boot.

Controlling Concurrent Runs with Perl

Sometimes you have a program that can’t be run by more than one person, or one that must run frequently but you don’t know for sure how long an instance of it will take.

Web site IP Filtering

We’ve talked here before about filtering IP traffic by source for mail servers.

Spotlight, mdfind (Mac OS X Tiger searching)

Most users will probably see Spotlight as an enhanced, very fast file searcher: something that builds an index of files and their contents, and can very quickly search that index and return results.

Unixart: Tracking Site Problems

As some of you know, I have Foo-web.com and some other sites on another web hosting site. Recently I noticed that I’d frequently get locked up for thirty seconds or so while editing files on that site.

Beginning Web Development with Perl (Review)

While Perl may not be the “cool” language for websites anymore, there are some of us who prefer to work with it because we use it for so many other tasks.

Programmer Overkill (MySQL)

I have a peeve about MySQL. Oh, not about MySQL directly: it’s great. I love it, it’s wonderful, no complaints. It’s the people who use it when they don’t need to that get me shaking my head and talking to myself.

Domain or not?

Computer networks are often just automatically set up without much thought: if it’s a business, it’s set up as a domain, if it’s home, it’s not.

C++ or C (or both?)

Some of you may have made use of Dean Jones’ CleanCode Email. It’s a nicely done mail sender – it’s not an SMTP server, it just sends mail, but lets you specify the gateway or smart host to use, which makes it wonderful for systems that don’t need to receive mail.


Linux “symlinks” is a handy utility for managing symbolic links. It can clean up the sort of problems that come from carelesness when creating symbolic links.

NBD (Network Block Device)

Bird’s eye view: you have a block device, for example /dev/nda. It acts like any other black device, which means that you can create a file system on it, make it part of a mirror or RAID 5 array and so on.

Viruses and Unix

I was in a meeting last week where a customer was exploring switching from a Unix platform to Windows.

CSS Frustration

CSS is wonderful, because it allows the true separation of content and presentation. CSS is frustrating because it doesn’t.

Perl Binding,

Perl has “||” and “or”. While “or” can’t be used in bit operations, either one can be used in logical flow control – but there is an important difference between them.

A Bit of C Debugging

have a customer who has a hodge-podge of machines running various software programs. It’s all a mess, low on disk space, not every machine that should be backed up is backed up, and so on. I’m slowly working toward a better world on some of those things, but we still have to deal with the day to day problems.

Taskset For CPU Affinity

SMP operating systems have choices when it comes to scheduling processes: a new or newly rescheduled process can run on any available cpu.

HLA – The High Level Assembly Programming Language

I’ve noted before that assembly language programming can be quite engrossing. It’s the level of detail that captivates; there can be a great deal of craftmanship and mental challenge in writing assembly programs.

New Interfaces for Microsoft?

Microsoft tells us that their application interfaces need revamping. Apparently having eighteen kazillion commands buried under three million menus confuses people now and then.