Programming the Commodore 64: the Definitive Guide 245
Mirk writes "Back in 1985 it was possible to understand the whole computer, from the hardware up through device drivers and the kernel through to the high-level language that came burned into the ROMs (even if it was only Microsoft BASIC). The Reinvigorated Programmer revisits R. C. West's classic and exhaustive book Programming the Commodore 64 and laments the decline of that sort of comprehensive Deep Knowing."
6510 Machine Language (Score:3, Interesting)
All of the 8 and 16bit machines were knowable (Score:4, Interesting)
It was possible to fully understand all of the old 8 and 16 but machines. Now you could spend momths trying to fully understand one video card, which would be replaced by something more complex by the time you finished understanding it.
And that was a big part of it, the stability of the platforms during that era. A C64 was exactly the same as every other one, a Tandy Coco was identical to the million others of it's kind. Later models tended to retain as close to 100% backward compatibility as possible so knowledge and software tools retained value. Now you buy a lot of PCs with the understanding that a year from now you won't be able to buy more of the exact model even if you stick to Optiplexes and such that promote the relative stability of the platform. Something will be slightly different. So, understanding being impossible we abstract it all away to the greatest extent possible.
If you want to reconnect with low level look at AVR microcontrollers. If you are really frugal you can get going for $20.
Re:Totally outdated... (Score:3, Interesting)
V-Max (Score:5, Interesting)
Re:Indeed (Score:5, Interesting)
There doesn't appear to be any section on custom high-speed communication with the external floppy drive unit. IIRC, you could upload a small program to the drive, and then you could in particular read data from the drive a lot faster than the 'OS' normally supported. This technique was also used to do copy protection for a bunch of titles, primarily by stepping the drive head 1/2 between tracks then doing reads. Production disk duplication could write to both the track & between tracks [or could write a wide enough track to cover the whole area], but regular floppy drives couldn't write both [you could either write on the track, or between tracks].
Not that I was interested in this stuff or anything.
Re:Relax (Score:5, Interesting)
Uphill Both Ways (Score:5, Interesting)
Re:I miss those good 'ol days (Score:2, Interesting)
I think it's there if you want it. A couple of weeks ago I was writing in assembly language specifically for one of the top ten fastest computers in the world. Sure, there's a shitload I don't know about that cluster -- no idea if there's an RJ-45 port, much less how I'd access it via the assembler, but I could probably find out if I cared and got clearance for it.
It's easy to romanticize simpler times, and there is some truth to them being simpler, but I'm damn excited about today. I mean, really, you can the guide for ARM assembler and pick up a phone or other portable, and have a ridiculous amount of computing power that you can bend to your will. OS and application bloat is either for a purpose (e.g., to make a computer easier to program for, or to add more features for less work) or a result of laziness, but on most systems you can get down to ground level if you really want. It's just that most people do not.
Re:Invert rose-tinted-glasses (Score:3, Interesting)
Absolutely. This is the point of, for example, the STEPS project at VPRI, which aims to build an entire working system (kernel, GUI, dev tools, apps) in under 20,000 lines of code. Some of the stuff they've produced, like OMeta and COLA are really impressive.
Adding complexity to a system is easy. Adding features without increasing the complexity is much harder, but much more useful and rewarding.
How Fast Loaders Worked (Score:5, Interesting)
Re:Its still possible.. (Score:3, Interesting)
You are only partly right. All of those things are knowable and learnable within a reasonble length of time - the problem is getting the documentation to know them. Too much documentation is locked up as proprietary info, either behind a paywall or an NDA wall.
Re:Its still possible.. (Score:3, Interesting)
On top of that, I have postfix config files, a mach_kernel file, and a bunch of other weird files that are either quite complex (this book about Postfix is 288 pages [oreilly.com]), or I have no idea what they do, or they are binary and I have no hope of ever figuring them out. Even if I switch to my Linux partition, where I have the source code to everything, it's a lot of work to understand every single file in even just the Kernel. I'm not sure anyone even understands the Kernel itself completely. I haven't talked about hardware yet, but Intel processors do some tricky out of order operations and pipelining and such, it's not always easy to predict what is going to happen on one of those things. It is a lot of knowledge, and I am not sure anyone actually does understand it today, even if it is possible. No one I know makes that claim.
This is really different from the days of the C64, where the entire thing was only 64k (actually more with paging). You can read the entire memory contents of 64k in an afternoon, literally everything on the computer. You could definitely understand all the 'source code' (except the source code was in assembly) to the entire system. Predicting what the processor would do and how long it would take wasn't hard. You could fit everything about the system (even schematics to the hardware) in a single book.
Re:Relax (Score:4, Interesting)
Perhaps ultimately more dangerous(because they tend to be subtler) are situations where no law ever bans something, per se; but some quiet mixture of contractual, legal, and technical pressure effectively prevents it anyway. Consider SDI [wikipedia.org] for an instance of that. A digital video transmission standard, available well in advance of HDMI, that was frozen out of the "Consumer" market entirely. It's not like possession was illegal or anything; but most people never even heard of it, nor was it available on any broadly affordable hardware.
In the case of something like debuggers, I'd be very surprised to see any sort of legal ban; but the technological/private sector contractual de facto neutralization is an eminently plausible scenario. Already, in recent versions of Windows, any media application that requires the "Protected Video Path" will throw a fit if there are any unsigned drivers loaded that could compromise that path. An analogous "Protected Execution Path", provided by the OS for programs that didn't want anybody else debugging them or looking at their memory, hardly seems implausible. Not to mention, of course, the increasing percentage of consumer-level computer activity that is occurring on devices were being able to run arbitrary programs isn't even an expectation. Not much debugging going on on Xbox360s, and debuggers don't have to be illegal to not be available through the App Store.
There will always be gaps, of course, for the sufficiently knowledgeable, motivated, and well equipped; but a largely opaque consumer level computing environment seems like an unpleasantly plausible prediction.
Re:How Fast Loaders Worked (Score:2, Interesting)
The 1541 drives were purposefully slowed down to maintain compatibility with some other Commodore hardware (I forget at the moment exactly which)..... so they weren't so much fast-loaders as they were "doing it the way the engineers designed it to work, not the way the boss made them change it so he could claim compatibility.
experimenting and learning (Score:2, Interesting)
I had a 1 line game for the commodore series of computers.
Something like the below. You could do it in less than 40 characters with the short cuts. It even worked on the TRS80 line with slight modifications.
I liked walking into their sales rooms with the "don't touch serious stuff" feel and having a game going in 30 seconds.
0 poke 32788+loc,65; loc=loc+peek(151)*2-1; print tab(rand(37)),"XXX"; if peek(32788+loc) == 32 GOTO 0
You had to clear the screen and start it with RUN at the bottom for it to work
poke 32788+loc,65 # Display your lander "A" at the middle top of the screen+ offset
loc=loc+peek(151)*2-1 # update your location to the right if shift is pressed, otherwise to the left. No going straight.
print "XXX" # but a block XXX at the bottom of the screen and scroll the previous display of your lander A off the top
# the blocks would scroll up towards the top of the screen and you had to dodge them
if peek() # loop if you are not going to hit a block
It ran nice and fast.
C64s can still be fun... (Score:3, Interesting)
A computer that fits in your head can be great fun (Score:3, Interesting)
I've recently rediscovered the joy of small computers that can be fully understood by one person. The 8 bit machines from the 80s provide opportunities for learning and experimentation that are not present in today's computers. "Retro computing" is growing as a hobby amongst both people who remember these machines fondly from past days and younger folks who just find them interesting. It is strictly a hobby of course, very little "useful" stuff can be done with these boxes beyond the education they can provide.
My favorite retro system is OS-9, a real time multitasking operating system that you can fit in your head. There is an open source version called NitrOS-9 [nitros9.org] which has excellent documentation and most of the code well commented. It runs on 6809 based computers like the Tandy Color Computer and the Tano Dragon.
You can learn a tremendous amount about process scheduling, IPC, memory management, device drivers and low level I/O, etc from playing with this system.
Excellent Commodore book (Score:3, Interesting)
http://www.amazon.com/Edge-Spectacular-Rise-Fall-Commodore/dp/0973864907 [amazon.com]
Re:Indeed (Score:5, Interesting)
Yet every day, I put young pups to shame. It does not matter if it is troubleshooting hardware, or software. It does not matter if it is dealing with programing or configuring. My mental map of the problem is different than theirs.
The skills I learned back in the 80's on a computer that you could understand, I still use today. My "concept" of what a computer is was formed by understanding the whole. RAM, ROM, interrupts, I/O, how the CPU works. All from a machine with 64K or RAM and 20K of ROM.
Under the hood, under all of that abstraction. Is a PC that is very much like a C64. With the C64 people learned mastery of their system. With the PC, so much hardware is out there. It is impossible to learn it all inside out and take advantage of every feature of it. So greater power has always been obtained in the PC world by moving to faster hardware, not by utilizing the current hardware better. It is all abstraction running on very fast, underutilized hardware.
The techs coming out of college for the last 20 years do not understand a computer conceptually like those who learned this stuff in the 70's or 80's. When it comes to trouble shooting all of this abstraction, many folks have no idea that there is anything beneath the abstraction.
I recently attended a college programming class as a requirement for a degree. The instructor gave us a quiz at one point and there was only 5 students out of 60 that passed. Why? Because most students did not know how to write a program on a piece of paper. Without intellisense holding their hand they could not code. I learned to program from the manual that came with my C64. I learned to program better by typing in programs from Compute! Magazine. I have written hundreds of pages of code on paper and typed it into a computer at a later time. It is a skill I take for granted. Without the abstraction of Intellisense most of the class was rendered useless.
Something has been gained, but something has also been lost. When I was a kid I dreamed of computers that could do a 10th of what they do now. I learned everything I could about them. Lived, dreamed, ate, slept computers, computers, computers. Now days. My kids can buy a laptop with 3 gigs of RAM for the price of a C64 and 1541 drive. And what do they do with it? Program? Nope. They learn their friends on FaceBook, not programming. They play games, not write them. They pirate music, not create it.
It looks like those who understand a computer and really make it do something will always remain a small, elite Priesthood.