Though I'd been exposed to computers via my mom's work at the Princeton University Computer Center in the 70's (some of her students went on to Bell Labs to work on their particular development of Unix), I first got my hands on them in 1981, as a database tester at a large Boston corporation. They were still using a mainframe/batch processing/punchcard system. (Yes, I punched some of my own cards.) Soon they switched over to using IBM 5280's with ridiculously huge floppies for media. (But I remember thinking at the time that this technology would be well suited for organizing music. Sure enough...) Then the first IBM PCs showed up a couple of years later, along with 3270-series terminals. Somewhere on a 5 & 1/2" floppy is a GW-Basic program I wrote to generate the harmonic series... (You know, root, octave, fifth, next octave, major third [sort of], etc., ascending.)
Concurrently at home, I messed around a bit with a housemate's TI-99 (my mom had one as well) which had a primitive sequencer cartridge you could plug in; step input only. (I remember inputting "Kings and Queens" by the old British art-rockers Soft Machine.) And like many penniless musicians of the time, I opted to use the Commodore 64 for MIDI sequencing, starting in early '84 when the MIDI revolution began to take off.
Then another housemate who worked for one the deans at Harvard got the academic deal on the first Macs. I immmediately took to it, not for music (I couldn't afford a Mac myself) but for desktop publishing. But it was obvious that this was the way to go eventually, and I at least got some general Mac OS experience out of it.
Later on I switched from the C-64 to the Atari ST and a great sequencing/notating app called C-Lab Notator (ancestor of the popular Emagic Logic line of sequencing/audio apps - I now use Logic Audio Platinum on a heavily upgraded, loaded and tweaked Mac clone.) As the 80's gave way the the early 90's it became apparent that the Ataris weren't going to be able to keep pace with the addition of digital audio alongside MIDI sequencing - a shame, since they were the tightest in MIDI timing of all the music computers. (The MIDI interface was built in; the only other boxes ever to have that feature were the Commodore Amigas. To this day all other computers need MIDI interface hardware of some kind, attached to serial ports or, these days, usually USB ports.)
In Spring '92 I began working with a programmer/musician friend who was running Opcode's Studio Vision on his Mac IIx and so got my first taste of an integrated MIDI/digital audio environment. The year before, I'd taken a class at The Lab in San Francisco with Australian sound collage artist Fran Dyson, learning Digidesign's Pro Tools and Sound Designer and OSC's (later Macromedia's, and now Bias's) Deck. But those were digital audio only, other than some synchronization hooks in Pro Tools for running concurrently with a MIDI app.
A couple of years later I made the switch over to Macs fulltime. I've owned, let's see, ten of them so far... This is being written on the most recent, a laptop running OS X. I've occasionally run three OS'es simultaneously on it, all running internet connected apps - OS X, Mac OS "Classic" (OS 9.2), and Windows 98 (under Connectix's Virtual PC - I can test most cross-platform stuff this way.) I could run a fourth OS, Windows XP Home, as well, also under VPC, but it's such a memory hog, and its interface seems to confuse simplicity with simplemindedness... ;-)
In the early to mid-90's I added some Unix knowledge to my skillset, as a Unix shell account was the main means for getting on the Net in those days. (In my first month or so on the net, I spent a lot of time downloading Atari apps from FTP sites in the UK and Germany... And the Jan' '94 Northridge quake was the first event I heard about from the Net before hearing or seeing it on the regular news.)
In '94 I moved into a house with other geeks, a venture initiated by a couple who were some of Wired Magazine's first employees (he kept their network up and running, she was the ur-employee of Hotwired, their online version), where we set up a home ethernet system hooked up to an ISDN line, and later various Web and mail servers. Until I left the West Coast, Centerverse existed on my own (Apache) Web server and procmail-based mail server (using Unix emulators WebTen and MachTen for the Mac from Tenon Intersystems), sitting on the ISDN (and later SDSL) link on my back porch. These days it's hosted by my ISP on the next best thing, Linux servers. Eventually ($$$) I will move it all back onto Mac OS X boxes, since OS X is Unix, with full hosting capabilities, especially the Web's number one Web serving app, Apache. Tenon makes a great front-end package for OS X's built-in server capabilities, called iTools (not to be confused with Apple's Web services of the same name, which I also use.)
After my crash course in networking and Website editing (from '95 to '97 we ran a popular emerging diseases information site from our house - outbreak.org - where I learned a lot about information design through our interaction with experts in epidemiology (from the CDC and elsewhere) and journalists), I turned to freelance Mac consulting and troubleshooting. Then, when a friend who was the IT guy at a rapidly expanding ad agency (18 employees to 70 in less than a year) realized the workload was becoming too much, I joined them and became the "daily brushfire guy", dealing with the day-to-day problems of the users, configuring and rolling out new machines and software as needed, running system backup tapes, etc., while he dealt with the more long-term strategic planning. (Success and expansion at a company can be at least as challenging - avoiding "success disasters", as a former housemate once put it - as failure and contraction, if not more so. There are generally more balls in the air at such times, to be sure.)
So, twenty-odd years after first falling into the gravity well of computing, I find that it has done more far more than enhance my compositional craft and give me a corporate skillset- it's provoked my interest in areas such as information design, usability (since most computers and software are useful but not all that usable), and cognitive science (e.g., from watching users at the ad agency construct plausible but incorrect mental models of the problems they encountered.) In music school, I always found those students who were focused too narrowly on music and nothing else to be not only kind of boring, but also not as good musicians as those whose musical skill was leavened by their other interests. Computers have been, for me, not just another area of fascination, but one that ties together my musical interests with the others it's opened up for me.