Further operations

Debunking Debunking TMR‘s “Prepare To Operate – Part 1”

I‘ve been pleased to see an increase in the hits on this website, but I don‘t know where they‘re all coming from, except from various countries. As he hasn‘t even seen my stats, I don‘t see how TMR would know either!

The author’s pleasure is based on an increase in traffic, but he then states that he doesn’t know where said traffic is coming from. Your correspondent was merely pointing out that the author doesn’t even know that said hits were down to a real person reading his bile-laden drivel, so that aforementioned pleasure was misplaced.

TMR said he worked in London for a while in the late 1990s. This has nothing to do with what‘s been happening to London since then. The destruction of London has taken place just in the last few years.

And this entire discussion is, as already mentioned, completely and utterly off topic for a blog that the author claims to be about “explaining why the Commodore 64’s BASIC V2 was crap and how some people managed to program the C64” so the author can hardly complain about relevance when he himself is failing so abysmally on that front.

TMR claimed to live in Yorkshire. This is a county which was abolished in 1974! Its territory was redistributed amongst three new counties containing the name Yorkshire, as well as some old and new counties.

Yorkshire is still recognised as a “geographical territory and cultural region”, so claiming to be living in Yorkshire as your correspondent did is still perfectly valid and indeed in common use. It wouldn’t have taken much actual research to realise that, but past experience has taught us not to expect that kind of effort from the author.

Linux is an operating system which has been adapted for lots of different hardware. The way it boots up may be different on different hardware, but once booted, I don‘t think Linux depends on making any calls to a PC BIOS ROM, a Mac ROM, or any other ROM.

The author’s original claim was that he didn’t “think [Linux] depends on any ROM, because it can run on PCs, Macs, and Raspberry Pi computers” but, as your correspondent pointed out, it does rely on a ROM because it wouldn’t be able to boot otherwise. The “but once booted” qualifier in the sentence quoted above wasn’t part of the original statement and changes it significantly, so the author is once more trying to mislead his readers by moving the goalposts.

Linux used to be quite difficult to get into, but has now become fairly user friendly, although some distrtos such as Arch insist on making users type lots of commands to get everything set up. In spite of this, some Arch based distros such as Manjaro, and Antergos have added graphical installers.

Your correspondent’s criticism was based on the huge variety of distributions and the variations they bring to the table making it harder to get into, which in turn has inhibited the spread of Linux on the desktop; that’s a perfectly valid argument because the average user – who won’t have the time or indeed inclination to experiment with multiple flavours of Linux even if there weren’t “lots of commands” to type – doesn’t know or care what an “Arch based distro” is or if they should select GNOME, Cinnamon or KDE as their desktop environment. In that respect, Linux is still difficult to get into and probably always will be.

The Final Cartridge 3 desktop environmentThe author’s post topic was, specifically, the “Commodore 64 and Operating Systems” so we can only hope dear reader that the next instalment will actually talk about operating systems for the C64 since he’s struggling to do so at the moment! There has at least been a passing mention of Berkeley Softworks’ GEOS previously even if the author failed to go into any actual detail (it does fall outside his self-referential 1984/5 window of course, but so does all of the Linux discussion so he’d be almost ridiculously hypocritical of him to complain and doesn’t hold water as an excuse) but what about the other options available during or indeed after the C64’s lifespan?

And we’ll have to see if the author somehow manages to tie any of the operating system discussion into his blog’s stated topic during future posts or if the entire discussion must be written off as irrelevance.

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Prepare to operate – part 1

Debunking The Commodore 64 and Operating Systems (Part 1)

Welcome to everyone who has recently been viewing this blog so much!

Your correspondent notes that the author apparently doesn’t understand that the WordPress statistics include spambots, search engine spiders or perhaps content scrapers in with the legitimate views. Your correspondent has also noted several busy periods but wouldn’t automatically assume that meant a significant spike in visitors.

Unfortunately, I‘ve had serious problems working out what to do next in the quest to find out how some people managed to program the Commodore 64…

And we have to start dear reader by asking ourselves what on Earth the diatribe which follows has to do with that stated topic; all of the rather blatantly uneducated discussion of Linux isn’t relevant in the slightest and, as we’ve noted previously, sitting down and putting the time and effort into learning is how people managed to program the C64, just like any other computer.

…as well as being very depressed by the destruction of my home city of London. The city is still there, but has been made virtually uninhabitable to me, as well as its nightlife being decimated. If any of you are thinking of visiting London, don‘t bother!

This has absolutely no relevance to the author’s stated topic either but, if we’re going to offer personal opinions of London, your correspondent worked there for a while in the late 1990s and found it an unfriendly and rather depressing place even then. It’s one of the reasons your correspondent now resides in Yorkshire in fact.

Operating Systems are what makes computers go. There‘s some dispute about whether or not the C64 actually had an Operating System, though. Some books and magazines say it had, while other books and magazines say that an Operating System is something you boot into which isn‘t a language waiting for you to type a program in. As the C64 boots into BASIC with the Ready prompt, on that basis it doesn‘t have an operrating system.

The majority of 8-bit systems go to a BASIC ready prompt in the same way as the C64 and some of these systems have to then boot a DOS from disk whilst others don’t even have an official solution for attaching a disk drive to the computer in the first place. The C64’s DOS might not be particularly user friendly but it does come with disk commands baked into the BASIC interpreter.

And if, as the author claims at the start of that quoted paragraph, “operating systems are what makes  computers go” how do any of these machines actually “go” if dropping to the BASIC ready prompt equates to not having an operating system?

Unlike MS-DOS, the Commodore KERNAL doesn‘t have lots of routines which can be called up. It has a total of 39 routines, as listed on http://sta.c64.org/cbm64krnfunc.html . I don‘t know what routines are contained in the very messy Commodore DOS.

So the author is once more complaining about something he hasn’t properly researched or understood… and let’s pause to note dear reader that any computer running CP/M or MS-DOS was actually loading a third party operating system from disk so comparing it to the C64 without allowing the latter to do the same with something like a DOS wedge is both a false argument and hypocritical. So, although they’re a later example of a DOS wedge, your correspondent found four slightly battered Action Replay 6 cartridges earlier…

Four Action Replay 6 cartridges and friends

…including one modified to extend the freeze and reset buttons for use with a C128D[1].These are also third party programs which boot from an external ROM rather than disk but work in a similar manner, adding commands such as $ to read the directory, @N to format a disk, @V to validate, @S to scratch a file, @C to copy files and @B to duplicate an entire disk either via RAM or from one drive to another. There aren’t drive letters of course because Commodore computers use numbers so commands like @8 or @9 select the relevant drive for the other commands.Formatting a blank disk with an Action Replay 6 cartridge

For example this is how to format a blank disk for example, @N is the format command (short for “new” as in new disk) whilst C64CD is the disk label and 64 the ID.

Linux operating system is open source, which makes it highly customisable. It comes in lots of different varieties, called “distros” (distributions) meaning that the software included with each distro and how to install new software varies greatly.

This is off topic as noted earlier but okay… your correspondent would argue that Linux is actually too customisable, that the huge range of distros makes it difficult to get into as a beginner or even intermediate user and that said flexibility has more likely harmed rather than helped Linux as a desktop operating system over the years. Even for someone with a bit of computing experience it can be a painful ride, with desktop environments varying significantly and commands from one distro either not working or at least functioning differently on another.

I don‘t think it depends on any ROM, because it can run on PCs, Macs, and Raspberry Pi computers.

When a computer is turned on there’s some kind of ROM-based code in charge initially so yes, Linux does depend on it. In some cases like the Raspberry Pi it merely mounts the SD card’s file system and hands off control, but the average PC BIOS will go much further to the point of specifying which device the operating system is going to boot from and then handing over information about the system including RAM size and available drives.

At the end of the author’s latest missive  your correspondent finds himself wondering what the end game might be with this particular line of “thought”. Presumably he’s trying to build another worthless anti-C64 “argument” where not having an operating system (by some definitions at least) is somehow an issue but that’s easily debunked merely by looking at all of the users and indeed programmers who didn’t find that to be an issue either on the C64 or with other 8-bits which are similarly lacking in that department. There’s apparently more to come so we’ll have to wait and see where this goes next, and hopefully the author will actually be on topic next time… although that would be more than a little surprising if it were to happen.

[1] The Action Replay 6 cartridges are accompanied in the picture by a far more recent Turbo Chameleon and 1541 Ultimate 2 which can both, among many other functions, pretend to be one as well.

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Learning by the book – part 4

Debunking The Machine Language Book of the Commodore 64 – part 4

I‘m going to try and attempt to explain and demonstrate the very daunting tasks of drawing lines (the whole basis of graphics)…

Your correspondent has, in over thirty years of working with 8- and indeed 16-bit home computers, drawn game and demo graphics for all of the Commodore 8-bits including the VDC display of the C128, the Atari 8-bit, Amstrad CPC, Sinclair Spectrum, BBC Micro, Apple II and a raft of other computers and consoles without using either the BASIC commands or an assembly language equivalent for line drawing to bitmap and, despite knowing a lot of 8-bit programmers and artists, has never spoken to one who claimed that line drawing was “the whole basis of graphics” on their chosen platform.

Even programs such as graphical text adventures where the user can watch the display being built from a series of lines which are then filled in are created either with bespoke solutions by the programmer which allow artists to create the images[1] or using pre-developed tools like the Graphic Adventure Creator or The Illustrator (which is the graphical extension of The Quill) where each image is stored as series of commands.

If drawing lines really was, as claimed by the author, “the whole basis of graphics” and the C64 lacks the BASIC commands to do that, how exactly does the author explain the truly vast quantities of C64 graphics? Your correspondent will leave the reader to mull that point over and we’ll move on to find out which other task the author feels is only “very daunting” on the C64 but not other platforms shall we?

…and playing polyphonic music on the C64, which is child‘s play on other contempory computers, such as the Sinclair ZX Spectrum (drawing lines, but only playing monophonic music)

In other words only one of the two tasks is “child’s play” in this case because polyphonic music on the Spectrum’s beeper requires assembly language and precise timing, which is significantly more daunting than doing the same task with the C64 from either BASIC or assembly language.

Acorn Electron (one channel sound only)

Again dear reader, only one of the two functions that are supposedly “childs play” can’t be done from BASIC and needs daunting, complex assembly language whilst the C64 in BASIC or assembly language would once more be easier. The same is true of the Apple II, some earlier models lack a BASIC command to draw lines and only have a beeper for sound unless an expansion card such as the Mockingboard; even when that’s installed there’s no BASIC support for it so writing to the card is done via POKE commands or through a music composition tool just like the C64.

Again as an aside, if creating music is so much easier on other platforms there wouldn’t be any demand for the huge number of music composition tools including the one that the author himself used when composing on the Yamaha CX5M.

We‘ll need to decide which 6502 opcodes to use in our line drawing programs. It‘s fairly obvious that they‘ll include LDA #number, LDA address, and STA address, as well as loops including the use of LDX #number, and LDA address,X but not clear what else.

Tying to tell other people how easy or otherwise a programming task is without actually understanding the programming language is utterly futile. And programmers don’t make the decision in advance about which instructions they use in the same way that writers don’t pick specific words from a dictionary before drafting a sentence, they instead have their entire vocabulary available.

It turns out that [the Bresenham line drawing algorithm] was developed as long ago as 1962, on an amazingly advanced for the time IBM computer called the IBM 1401, connected to a Calcomp plotter. I don‘t know if the computer could display graphics on a screen, but it could plot them on the Calcomp plotter.

So the author claims that the IBM 1401 was “amazingly advanced” but apparently hasn’t even done enough research to know what the machine potentially has in the way of hardware; this makes any comments the author makes untrustworthy.

Unfortunately, Bresenham‘s algorithm is a complicated algebraical formula. This means I can‘t understand it because I‘m useless at maths, so I‘ll have to design my own alrorithm, based on calculations as simple as possible, as well as tailor made for the C64 screen mapping where the graphics screens are divided into 40 x 25 character cells.

No dear reader, the sensible way to program this would be to develop an algorithm which works with X and Y co-ordinates and then translate the values it generates for the C64’s screen. This is how all the existing line drawing algorithms work on the various 8-bit systems so the author is trying to reinvent the wheel without even knowing if making it a square would be problematic.

I think the C64 graphics screen can be located at any one of FOUR locations in Assembly Language, so I think first of all I need to decide where to locate it.

It can be at six; those locations are $2000, $4000, $6000, $A000, $C000 and $E000 or if only the upper half of the screen needs to be bitmap (which is quite common for things like text adventures with graphics) it can be at $8000 as well. Using $E000 with the colour memory at $CC00 means the bitmap won’t take memory away from BASIC, but the ROMs will need to be disabled whilst writing to that memory which isn’t a problem since the routine is going to be in assembly language.

Perhaps I could find out whereabouts this point is on the screen, meaning in which character cell by dividing it, but I don‘t think there are any 6502 Assembly Language instructions which do division. […] All there seems to be are the instructions LSR meaning Logical Shift Right, and ROR, meaning Rotate Right, which are both ways of dividing by 2 each time they‘re carried out.

So after saying that he didn’t “think there are any 6502 Assembly Language instructions which do division” the author immediately goes on to recall your correspondent talking about LSR and ROR which are assembly language instructions which can divide by two. The author isn’t even trying it seems because he’s quite literally debunking his own claims before the end of the paragraph they’re in!

Don‘t forget that Commodore‘s own manuals were crap! It took lots of third parties, often from Germany, like the author of this book, to unveil the secrets of the C64!

Don’t forget that Commodore’s manuals weren’t trying to teach this very specific task that, as your correspondent has pointed out previously, isn’t actually essential to graphics creation despite the author’s claims.

As for my other learning activities, I‘ve been studying Japanese, as well as programming in Python.

These are of course irrelevant to the author’s stated topic of “explaining why the Commodore 64’s BASIC V2 was crap and how some people managed to program the C64” and your correspondent is actually getting tired of having to point that out almost endlessly but will continue to do so. This might actually be a form of masochism on your correspondent’s part, but after all these years it’s difficult to tell…

I have completed 75% of the Michel Thomas Method Japanese Foundation Course, so this proves that learning to speak Japanese is far easier than learning to program the Commodore 64.

The author still stupidly believes that his personal experience overrides that of everybody else; this is another example of the “I know best” attitude that annoyed the author when his father exhibited it, making the author a hypocrite for yet another time. If a single personal experience made any major difference to this discussion then your correspondent could simply point out that he failied GCSE French whilst successfully learning 6502 assembly language for the C64 because that would completely negate the author’s “argument”.[2]

[1] This process is documented in the Steven Levy book Hackers which describes the process used by Ken and Roberta Williams whilst developing one of the first graphical adventures called Mystery House. Essentially, Ken rewrote the software that came with a graphics tablet so that it could store what Roberta was drawing as a series of commands.

[2] No dear reader, your correspondent doesn’t have anywhere near the self image required to believe his experience to be of such ground-shaking importance, he instead leaves such arrogant, egotistical and false beliefs to the author.

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