Wednesday, 20 August 2008

A Hacker's Introduction

Hello once more, or for the first time.

I figure that as I am no longer a part of the GNOME community, do not use most of their software, and have no interest in it I think my diary on blogs.gnome.org is no longer particularly appropriate. So here is yet-another web diary to add to the 3 or so stale ones I have laying about the place. I will start with a little introduction and history - since I don't have any great code ideas to share today. It isn't in strictly chronological order, but it should cover the important bits.

So, ... the story so far ...

The first computer my family owned was a Commodore 64. We just played some games copied from friends for the most part, and typed in the odd basic programme from magazines and books. I dabbled a little bit with programming - entering sprites using hand-encoded binary and making farty beeps through the SID chip. When one of my brothers bought another one, which came with a disk drive and a pile of magazines, it opened up a whole new world.

After typing in some 'acceleration' libraries from a Compute Gazette! (iirc) magazine I discovered the wonders of machine code, and subsequently assembly language. I typed in an assembler from one of the magazines - it extended BASIC with mnemonics, and you had to implement the 3 (or more) passes using FOR loops(!) and then taught myself 6502 assembly language from the related article and tiny snippets I found in various magazines. We lived in the country and had no access to bulletin board systems or much information, so it was all down to my own curiosity and probing. I can't remember how I learnt the rest of the mnemonics, perhaps a book in the town library or more magazine articles, but I ended up fairly proficient at it. I also can't remember where I got it from - perhaps I typed it in from a magazine too - but I ended up with a 'machine code monitor' as well (a debugger/disassembler) which let me disassemble demo's from magazine cover disks and learn further. I even wrote my own dissassembler (in assembly language of course) and dumped the entire BASIC and Kernel ROM's to a printer to learn further (reading the code subsequently I couldn't understand most of it ever again). Other bits and pieces were an interpolating printer driver for GEOS, and lots of other little useless toys, graphics ('vector' graphics, sprite multiplexers, raster interrupt stuff), and sound routines (a primitive sequencer iirc). I still used the machine to type my first few essays for uni.

Of course as a Commodore-head I dreamed of an Amiga, and finally got one during my first year at uni. Of course the first thing I did was borrow a book on 68K and hand-assembled a matrix multiplication routine to accelerate some 3d graphics in the horrid BASIC the Amiga came with - at least it came with a language though. I'd heard about fish discs from magazines, so I soon got the fish disk with A68K on it, and slowly collected other tools and got to work - learning M68K and hacking up code on a floppy-based system. And yet it booted faster than my latest GNU machine does (and just as well, it sure rebooted a lot more often too) and the editor was more responsive. Graphics routines, interrupt queue-based blitter 'engines', 2d stuff, 3d stuff, even a mod player routine. The golden age when all was learning and no other distractions like life to get in the way. Using snippets from magazines and books (the university necessarily had a much better stock of technical books) I read up on assembly language and hardware and i/o registers and all the rest.

Then I got a modem. At this point the internet didn't really exist - usenet was around, and ftp was just starting to pick up - but you could only get it at uni. That opened up access to other software, and other people, and I got in touch with a 'demo group' who wanted a coder for demos. We never really did anything to speak of, but we had a lot of fun being creative, and trying to mix real-time code, graphics and music together. Along the way I got an Amiga 1200 - having a hard drive was a nice step up.

It all lead up to a fateful Easter Long Weekend where I managed to stay up for 73 hours straight working on our demo, attended the demo competition, got disqualified for a silly optimisation mistake which had it fail on the target hardware, slept an hour on a plastic chair with my head on a Laminex table, had an external floppy drive stolen, set up for a video presentation at a rave/dance party, blew the 'blue' output of my 1200 (everything turned a yucky mustard grey/yellow) from a dodgy home-made video cable which shorted out, stayed up all night helping run the visuals at the party, and nearly had several accidents being driven home by a friend who all but fell asleep a the wheel mid Monday morning. I think I've been tired ever since, but maybe that's just a coincidence (sleep aopnea diagnosed years later). Although I kept coding on it, and even bought new hardware, I think the golden age had passed - for me and Commodore.

I got the ROM Kernel Reference Manuals and started writing more OS-friendly code rather than hardware-banging stuff. It was still in assembly language though. A little multi-threaded file manager I never finished, my MOD player routine came along about then. I dabbled a little in extending Amiga E - but couldn't maintain interest - my contribution was a 3-d library written in assembly language. Amiga E was a bit like Pascal but had an outrageously fast compiler - 45K of machine code - written by the clever and nice bloke who also wrote the first BrainFuck compiler - 1024 bytes of compiler which generated executables directly. I wrote a freeware extension to the AmigaOS's multi-media platform - datatypes - which read and displayed GIF files much faster than anything else. I learnt a lot of stuff about the importance of latency vs throughput, asynchronous I/O, threading and optimising code (it was all in assembly language), even what OO is all about.

Linux started to show up around me about then, along with the growing internet. Many GNU tools made their way to AmigaOS too, and I started to learn about the FSF (at first I couldn't believe anyone would give away such software - let alone the source-code, none of which I could use anyway). Eventually a mate had a cheap motherboard going and this new 'Linux' thing seemed to be getting more usable, so I bought a PeeCee and stayed up all one night with him trying to get RedHat 3 (I think?) going on it. After failing to get anywhere, I tried slackware and it worked. Suddenly I was in the world of pain that is the IBM compatible PC! Things get a bit hazy there. Work, life, and whatnot, too many very late nights doing geeky stuff with mates or IRC or other stuff. I can't remember what I used to use the Linux machine for other than internet access and compiling applications. I had learnt C by this time but I can't remember if I even wrote any software - other than for work, which was the occasional portability patch or hacked up Perl scripts. With a bunch of mates I helped run an ISP for a while, I lost some money, some lost skin through stress. A bit of a dark period I guess, which put me off the idea of ever wanting to run a business.

After the positive experience with the gif 'datatype', and sending in the odd patch here and there at work, I slowly became more interested in writing software as a hobby for free again, but this time including the source-code (I regret now that I never released the zgif.datatype source-code, such as it was). The KDE project looked very interesting - but I don't know if it was the GPL issue back then or perhaps C++ scared me off, but I never tried it again. I became involved in the GNOME project around 1998 - working on what would become the (now long-gone) second iteration of the GNOME Terminal application.

I started work on libzvt because I had had the idea from some terminal application on the Amiga which didn't have to 'copy' the lines it displayed. It just used Copper (a video co-processor) tricks to scroll by just telling the video DMA which lines to display, rather than re-ordering them so they displayed in the right order. Of course, on an X Windows display no such facilities were available, but I used similar ideas to optimise the screen update and minimise memory allocations - and by the end it was a pretty bloody fast and solid piece of code. Since I did much of my work on a Solaris box - which had an awfully slow malloc, re-using malloc's was a big win. Unfortunately nobody else working on the code-base ever understood why I did it that way, so patches came along and removed this desirable behaviour, and slowly I lost interest in maintaining it - because of a bit of a loss of direction for it, because I was too busy on Evolution by then, and because my ownership of the application had been undermined by someone who wouldn't let me do a few things I wanted. However, before then my work on libzvt/gnome-terminal got me a job working for Ximian (as #8) on this new 'Evolution' application.

Actually I never really had much of an interest in Evolution (I was a die-hard Elm user!), but I ended up working on it for 6 years. Rather interesting times. Working for a startup like that was really a unique experience. We worked like maniacs for the first year and produced tons of code - I don't know about the other guys but I never really expected to make gazillions like some other startups, but it would've been a nice bonus - so it wasn't the money driving me. I'm not sure i'd do it all again but certainly some of it was worth it. I do wish I'd known what I know now about programming and design, although I don't think we really made too many mistakes given what we were working with and aiming for. I always disagreed with the clone-MS aspect of the project - we all thought we could have done better, and I still think we could have. I would also have used CORBA more, and more effectively - but without a fully working ORB in the early days, and since most of us were busy just getting things working, I guess it was always going to end up the way it did. I also would have kept things simpler - but it is hard to know how simple something should be before you've done it once or twice. I think the project worked quite well considering few of the developers resided in the same city as any other, let alone the same timezone. Although it wasn't all sweetness and light ... I had a lot of nasty conflicts with inexperienced management (not all their fault I'm sure) and was wildly out of touch with many goings on by virtue of being literally on the other side of the planet. It was probably saved by virtue of the code-base being easily compartmentalised into chunks one or two developers could tackle in almost total isolation. And I got along reasonably well with Jeff on the mail component once he came along.

Novell buying Ximian was a double-edged sword. On the one hand they had money to keep paying us, on the other they started pushing uninteresting things like Groupwise backends into the mix. We already had a pretty low opinion of Groupwise from working around it's external protocol bugs (not as bad as Exchange mind you), and they threw inexperienced programmers at the task who didn't write very good code to start with, so the opinion didn't go up. Also being part of a larger organisation meant simple one-on-one management and a flat management structure were out the window. Now you had the over-paid baggage of a HR department breathing down your neck for pointless 'objective management tool' reports which they made you fill out on fear of death (which I might add you needed internet explorer to access properly - or maybe i'm confusing that with the expenses system which needed the MS proprietary Java). Other niceties were the yearly business ethics forms you had to fill out to cover their legal arses, and being told in no uncertain terms that you were there to work for the company and they had no obligation to give anything back in return. Even if they paid well, this was a foreign (and offensive - workers are not slaves) concept having grown up in a blue-collar slightly-pinko family during the Hawke/Keating years.

Ahh well. Anyway, we kept struggling on. I wrote a lot of code which never got used (actually some of it did eventually, in a changed form anyway), which is a pity, but by the end I was very burnt out on the project. Novell didn't really have anything I wanted to work on, or wouldn't let me work on projects I thought were potentially interesting at the time (e.g. Mono). And I couldn't come up with a project that they would let me work on either. I despised HR, and no longer had any interest in Evolution. So after a fairly extended and quite complete hand-over period of the Evolution code-base to the Bangalore team (I think I did quite a good job - although compared to any previous hand-over efforts, any job would've been an improvement), a fortuitously timed redundancy let me let go of all that and move forward. I found the hand-over quite cathartic - during the last few weeks, as I 'brain-dumped' 6 years of background into a few wiki pages, I felt more relief as each paragraph and section ticked off. Since then I haven't even run Evolution - I still cannot bring myself to, nearly 3 years later.

Since then, I've been working (for money) on a .NET, WPF desktop application! Bletch. Well, at least I can now say with confidence that MS stuff is awful. What a badly documented, sourceless, buggy, slow, dead-end piece of still-born technology this is. Well it pays the bills, but I will have to see what happens after this - I don't think I can keep it up.

Apart from work, I was pretty burnt out after leaving the Evolution project. I had a fairly long break from just about any sort of hobby coding. I'm still not sure where i'm headed. I've become more 'militant' Free Software - I never liked 'open source' but now I see it as highly damaging. Commercial interests are muddying the waters and trying to impose their corrupt way of business onto Free Software, and it really stinks. I joined the FSF.

I dabbled with AROS a little bit - but although they seem like a nice bunch of guys, I couldn't get terribly inspired. I wrote them an AVL library though - and that got me interested in C again for a while. I also dabbled with some other ADT's, and memory allocation routines, just some nice raw code to try to blow the c-hash cobwebs out of my head - and it was a true joy to return to Emacs. I played with literal programming systems along the way, but I can't make it work for me - the authoring is ok but debugging and writing libraries is not so nice. I even read a bit about ADA and Scheme and Lisp, although none of those inspired me either. I looked at writing a vorbis decoder. I wouldn't mind learning more about signal processing, and I just wondered if I could do it from the spec. I didn't get very far though - it has quite a nasty bit-stream format, and that scared me away. I did quite a bit of work on a content management system/blogging thing. I had some ideas on database versioning and document processing I wanted to play with, but have exhausted most of them now. Cheap branches, automatic indexing/toc/cross reference generation, web-friendly and print-friendly and not too author-unfriendly. I will get back to it if it becomes fun again, but who knows when that will be.

I have a Playstation 3 with Ubuntu installed, and have written a few little CELL routines. That is a lot of fun - I really love the architecture - it deserves success outside of super-computers and game consoles. But I can't really think of anything useful to do with it yet. At least, something useful I can do without it being too big a project for one man and his spare time to contemplate. I have some job-queue stuff, a bi-linear up-scaling routine and YUV to RGB converter. Just with that patched into mplayer makes quite a difference.

Well, that is pretty much got to today. As for the future, well more to come no doubt.

1 comment:

PTET said...

Hey man! Welcome to the blagospheric wilderness :)

My first computer was a ZX81... but the closest I got to hacking was some password crackers and running "Xmelt" on all of the Sparcs in my University computer labs...