Voyager #03
19 октября 1998 |
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Laboratory - ZX-SPECTRUM and operating systems.
(C) 1998 VY Chertkov Music: THE BEST ITALIAN-'VENICE 'by KENOTRON ZX-Spectrum and operating system (OS) More recently, asking anyone spektrumyuzeru question: "What is an operating system for Why did she want? ", you could get the answer: "I do not know!" And it is not surprising, since ever existence, on the Spectrum never had OS fully understood, because it was originally a computer conceived as a game. As in all such PC, at the Spectrum instead of the OS was installed BASIC in ROM, as This language has the basic features inherent in operating systems. But Spectrum BASIC is very primitive, does not support disk, press tokenizirovany (very poor syntax), and develop it further is extremely difficult. ROM Spectrum is built according to the "monitor" - there are no functions available to the user devices to service a computer with a single interface (in normal computer is called the BIOS or Kernal). There is only one standard entry point Monitor (restart) - everything else described in various literature on the Spectrum - a sub-program monitor, and nothing more. Ie, ROM is a "black box" which can not climb. Unlike the computer that Yamaha. Model MSX-1 is also, like ZX-Spectrum has only BASIC in ROM, but the Basic is much steeper than Spectrum and imagined future use drive. In addition, it is similar to Microsoft BASIC, but greatly expanded - supports graphics (Sprites) and sound (AY). In addition to BASIC, the ROM contains the system BIOS, and it gives the opportunity to develop all the basic software with no loss of compatibility, since No one inside these programs does not climb - there are standard entry point. In general, their own ROM has every device (RS-232, RTC 'CMOS). Program tied to any external events (input-output to tape I / O RS-232), not synchronized program delays CPU, and based on a real time clock, ie on CPU speed correctness of the drivers are not independent (compare with the Spectrum). Moreover, the functions BIOS available to the user's software - it's just wonderful: firstly, there is independence on the equipment, and secondly, to write programs much easier, because all low-level I / O is already created! In the model of MSX-2 was without problems is running MSX-DOS, ie, computer worked without the BASIC, though, if desired, it can be run on the OS commands. After restarting computer, in the absence of a system disk in the drive, also carried out in BASIC. Ie without OS computer looked like a normal MSX-1. But Basic was already a disc - all teams to be forwarded from tape to disk (without any RANDOMIZE USR 15619: REM :....), although the possibility of working with cassette remained. Old tape of the program worked fine from the disk, they did not have to be adapted to great difficulty, both on the Spectrum in TR-DOS, their had to just copy from tape to disk - and all! And I said all this to the fact that if Spectrum has been designed as a human, then many would problems now did not exist. No need to kid ourselves, not even in the hardware capabilities of the case, the underlying ideology of the computer is outdated! In the form in which there is now a Spectrum, it pointless to develop - the next revision will not change anything, on the contrary - the car will be even worse. Looking for a qualitative change. After all, the Spectrum was developed as a cheap gaming computer, but we are now with him cope, as a professional machine. Even Clive Sinclair himself by 1984 had lost interest in him because he was already obsolete, but we're still sitting, and that is trying to from him to do .... Almost as primitive as the ZX-Spectrum 48, were his competitors - C64 and Atari. But these firm in time changed his mind and released the brand new 32-bit model, having nothing to do with the old 8-bit. 32-bit Spectrum QL failed, of course, very sorry ... For the development of the new ZX took firm Amstrad, firing again very bad model Sp128 +, +2 and +3. They are very not far removed from the Spectrum 48, while the price has increased significantly - the sales speak for themselves. A after all there was also an opportunity to make a good, albeit 8-bit, the new Spectrum. Would take the CPU Z-180 or Z-280, which almost fully compatible with the Z80, at the same time more productive and memory addresses 1MB and 16MB, respectively. Some programs on These processors would not have gone, but no great loss. On a new PC can be fitted normal OS to support the older programs can be done something like an emulator, though, if you look at it up to 1985 good games, we can say never happened. Yes, many things could be done. Instead, concocted something called Spectrum 128K - apparently developed this "after yesterday." What was done in this model - it is done hastily and not the best way. In the same wells and the memory is addressed more convenient, and there are no such restrictions, as Spectrum ... Recently, many electronic publications raised questions of further development Spectrum, the comparison of different models for "Slope", and some places have begun to realize that the OS in general, it is necessary. And asking someone whether he heard about operating systems, you can get the answer: "Did you hear, hear" - referring to the TR-DOS, iS-DOS, CP / M or MS-DOS. But, first things first. The fact that the TR-DOS in general is not an operating system, written even in the corporate governance (read instructions can sometimes be useful) it's just a disk interface. When conceived this interface, the main task was to approximate it to the cassette, ie, that all operations were as much as possible like the similar "cluster". The meaning of the interface - just broadcast Cassette I / O to disk. But even that turned out pretty poorly - everything needed to redo the program, and relatively easy to distilled Only the most simple program loader on BASIC. Funny, but when craftsmen recreate BETA-DISK for "our" spare parts, apparently for reasons of compatibility with the ROM in 1990, the window entrance to the TR-DOS was shifted to 256 bytes forward - at the beginning of character generator (at address 3C00H on 3D00H). It is easily seen by looking at software, "throw" Multiface-128. In the "old" BASIC such programs, it happens, stays loader, where it is clear that TR-DOS command is invoked like: RANDOMIZE USR 15363: REM: LOAD "file" CODE On this basis, it becomes clear why no one (!!!) program TR-DOS, which came to us from the West - they just did not work. Another interesting fact is that the beta-disk - this is the worst of disk interfaces ever created for ZXSpectrum, and he settled down with us! And even in an erroneous implementation. What do we have a country that survives only in her worst ???.... And, in general, TR-DOS reminds the Monitor Spectrum, ie has the same shortcomings. At the same time occupies entire 16K - although such a "system" and 2 kilobytes much. Challenges for 3D13h - it's not BIOS (Ie, primitive, even for BIOS) and much, much less DOS. If you're not lamer, you will agree with me. As and BASIC, ROM TR-DOS to develop practically impossible - to begin again the problem (in) compatibility. Another thing iS-DOS - goes for any Spectrum, works pretty fast, here are some screaming: "iS-DOS - Best Of The Best !!!!" - Not fully understanding the meaning of these words. Although she quickly separates file panels, working with sub-directories, has external command, etc. In general, creates the illusion that your computer is running the OS, but it's worth a look in the programmers' manual - as all will become clear - it is just a wrapper, empty, You blatantly cheated! No OS and No trace. And if you're taking this leadership will come to more or less prepared for the programmer Amiga or PC, and start him to prove that the iS-DOS the operating system (I'm not talking cool) then, at best, he wagged his finger to his temple (Or call 03). All that is there - a set of functions for drawing windows, text output and input characters from the keyboard. File Subsystem (Part Operating system, manage files) is missing completely. Also, there is no memory management system, what is done - is in its infancy. And if it is compare, for example, MS-DOS, then this level of BIOS, ie simple device drivers. Yes, and how drivers they are defective: there is no clear structure, uniformity of input and output parameters, connectivity, custom drivers (like on PC). In normal system, all low-level procedures constitute the system BIOS, and to connect the extensions (plug-drivers), there exists some mechanism in the iS-DOS is a mess. No not that clear, in general there is no structure, And it is with the structure and begin to write the system .... Before writing the OS, you must first work hard to know what it is and how it works. I remember how they told me this system bummer. After reading in the advertisement: "... The newest operating systems! ... Subdirectories ... just can not believe this is unbelievable!" - Of course I was delighted and immediately ran to the post office to order the basic kit (in Inforkom, of course). Imagine my disappointment when I was at all it looked - it's just indescribable. So break off! Even formatter was not, but, by the way, this basic set, I copied the first same day they are even the same utility ARZT (or a Doctor, not I remember already, as it was called), such that's the case. I certainly have nothing against the authors this program - they did a great job, but Unfortunately, all for nothing .... Now we discuss the system CP / M. Many (Not all, of course), who saw the CP / M to the pros, why is convinced that CP / M - is the actual panel file shells CopyK, although it is certainly not the case. Interesting, but similarly judged and the MS-DOS shell to Norton Commander. Seeing how slow CopyK, many will say: "CP / M - this shit!". But it all that CopyK - it's just a program running under CP / M - and the fact that she ugly napisanz does not mean that the CP / M system is bad. It just means that CopyK - brake program! And CopyK we must pay tribute, in a time when it was written (92-93g), on the Spectrum nothing (!!!) this was not observed, although generally it and now the situation has not changed much. OS CP / M - is an add-on equipment computer, the intermediary between programs and devices. At the disposal of the programmer is a set of functions, which greatly simplifies writing programs. Those who disketiroval game in TR-DOS, they will not believe how easy it is to work with files, even in standard CP / M (on the extended versions, I do not say). System provides ease and convenience working with file structures. Program, working through the CP / M, will work on a floppy disk, a screw or electronic drive - to work on another device, it should just go copy and do not need to redo it. Complex manipulation sectors, tracks, teams controller - all it takes the OS. You do a direct solution of the problem, rather than recreate some parts of the OS at each program (as is well known, qualified in all different programmers ...). * TO BE CONTINUED * fragments of the OS at each program (as is well known, qualified in all different programmers ...). * TO BE CONTINUED * vobodnoy from the intro of - Why? - I do not know! (C) 1998 VY Chertkov Music: SPECIAL COMPOS 'by KENOTRON'96 ZX-Spectrum and operating system (OS) (Continued) Now for the visual comparison of the systems. The point that "see" the operating system can not, ie because this is just a set of functions - is not a program such as musical demonstrations - which draws chtoto on the screen to the music - it's not something ... System can only be assessed on their abilities (Both existing and possible future). Although, like it is! The magazine ZX-Format N4 Nemo, reflecting on the Spectrum, gave a comparison of existing systems to ZX. We compared the CP / M, iS-DOS, TR-DOS and MagOS (!). Nemo, not stupid like a man, a good article says, but he thought of comparing CP / M with MagOS? It's like comparing a scooter with a "nine". After all, people are not very versed in this, after reading the article have thought that the program MagOS on Scorpio - is a system comparable to the level of CP / M. The same just wild! And indeed, in this series CP / M - is the only operating system, so I do not understand how they can be compared. Despite all that, in comparing these systems won, what do you think, what? Yes, all right, iS-DOS! In CP / M, it appears, and the interface is not (I wonder how it all works then?), And segmented, and "long" files. You are wrong, all it is, why it can not not be. The only thing the human Nemo - subfolders in the usual CP / M actually no, but there are areas of the user - USER'y. I agree that working in the command line is not very convenient, but no one did not make work exclusively in it (you're in MS-DOS too both work?) - writes the file wrapper, and all becomes very cool! The main thing that has not considered Nemo: CP / M - is a real OS, and as a consequence, is able to develop and improve (example - system DOS 4.0 (the pros) is compatible with CP / M and supports subdirectories). I certainly understand that iS-DOS was created in his native city for Nemo, but all well, you can not be because of this so biased. Reading the various journals and newspapers, I noticed an interesting trend: Many agree that the OS Spectrum is needed, but everyone wants to create its own system (naturally, VERY BEST), which has nothing in common with the previously existing ones. Since, in their opinion, all the old system - bullshit. As a rule, these people already have achieved some success: created several dem (And possibly very steep), intruh, disketirovali a variety of programs, etc. But, I dare say if you've written at least 50 superkrutyh demo, it is not means that you create at least one operating system (the opposite way, too true). Yet the process of writing the demos and the OS is slightly different. Many simply do not understand how difficult to develop an operating system from scratch. After all, you must fully think through the system, for example: 1 How it will interact with the programs external devices and their own components; 2 How to be organized by an external memory (in the form files or otherwise); 3 How the system will allocate memory, includ le extension; ie, how it will manage the PA myatyu; 4 If the system will manage the files, it will be whether to use any of the existing filesystems (ekstentnaya CP / M, FAT, NTFS, HPFS or another) or will be developed Sauveur Shannon new file system. 5 What status will be launched programs we have: serial or parallel processes, substituted modules or something else. 6 In what form will be a dialogue with users Telem: as a command line, menu, or the Picts gram. In this list I bring the first thing that came to mind, it has a lot left out! In addition, the program control external devices (drivers) should written by a man, at least a little knowledgeable in hardware (preferably - good). Take for example keyboard driver. Some may say: "No could not be easier, and will, of course, wrong. What I have seen enough in the same demah and email. magazines like crooked interviewed key! here and unrepaired chatter, zavivisimost speed replay (Repeat) and the delay before the first repetition of the clock frequency of CPU and other defects. When Reed's software keyboard, and he know does not know that there is such a thing as a "bounce" keys (one must understand the physics of the phenomenon). Wrote calmly program, they had to work fine, but only with him. At the other company - is continuous glitch. Or another example - the procedure for loading the unit with a tape recorder (the same 1366 or # 0556) how many people understand thoroughly ee? A because it was the most simple examples, but there is still extended memory (also there is not so simple as it may shown), mouse, disks (it is not very difficult) other devices ... The device driver should be the absolutely correct no matter from which, as it was his duty - that's why it is written. Leave podprogrammki, anyhow, if only work is not difficult. Modules that work well not only on the machine of the author and do in any circumstances, create a much more complicated, but still, and they must occupy as little memory and run as fast as possible. To develop and implement a new operating system can leave year 2-3, not counting time spent on testing, error correction, etc. In addition, a completely new system, there will be no assemblers no debugger, no programming language of high level - nothing at all. The question is, who and why Such a system is needed, whether it is 10 times steeper than MSDOS, Windows NT or AmigaOS? For example, when creating MS-DOS, the authors do not steel puzzle, but simply took as a basis for CP / M and improve it. Almost all software from the CP / M was easily moved to a new OS (was even a special utility that allows you to translate the source code i8080 assembler code for a processor i8086). New systems for an 8-bit computers, which appeared after the establishment of CP / M, as a rule, have been with it compatible. That is, the system is a CP / M + "something else" at the discretion of the developer. Because creating a compatible system, not need to worry about the underlying software, as it already created: there is a steep and assemblers, and debuggers, and Languages Vysk level. Thus, to create a completely new system for an 8-bit computer that is not compatible with CP / M, totally meaningless. There is one very important point. Case that absolutely all of the programs for the ZX-Spectrum were created, given that the OS on your computer no. From this, in particular, that appears any OS, it run the program for the Spectrum will not (remember iS-DOS). All prog for ZX written on "naked" computer, using all available memory. The program is running any OS, in some way limited: they using only the available memory, to perform certain actions cause the operating system, after completion of the work through to the OS, but do not reset memory, etc. Thus, the conclusion suggests itself: Spectrum and any operating system are incompatible! The situation would seem hopeless, but still I see solution. Let's start with the fact that the interface TR-DOS - it is non-standard device, it does not support any one western Spectrum emulator for the PC, although supported by virtually the entire periphery, ever existed on the ZX. Standard is the same as It is strange - the tape recorder, or rather, in emulators these are images of tapes - tap-files. These files are "understood" any emulator, in addition, it at any time you can write on this tape and upload to the This Spectrum ... That is to say, the first time, not in favor of TR-DOS. It's no secret that the programs normally transferred from the tape in TR-DOS, there is little, each can find at least a little, but a glitch (that blocks marred, the picture, then use a different disc does not want to boot, it does not "understand" one-sided disk drive, then upload the disk does not work). A program on the tape is quite normal to work, without no problem ... Not only does the West program come up all the broken, when moving to TR-DOS are once more maimed. It is not often that the program is "purely" moved - now in one problem or the other. And this is the second time. Thus, in the long run, you can opt out of the interface TR-DOS, returning "back to the tape" - but at a new level!
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