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- From: kellerer@informatik.tu-muenchen.de (Ignaz Kellerer)
- Newsgroups: comp.sys.amiga.introduction,comp.sys.amiga.misc,comp.sys.amiga.programmer,comp.answers,news.answers
- Subject: Amiga FAQ (Frequently asked questions) (Part 1 of 4)
- Supersedes: <AmigaFAQ-1-824230821@informatik.tu-muenchen.de>
- Followup-To: comp.sys.amiga.introduction
- Date: 9 Apr 1996 16:00:25 GMT
- Organization: InternetNews at TUM, Technical University of Munich, Germany
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- Summary: Frequently asked questions on the Amiga.
- New users should read this!
- Originator: kellerer@hphalle3g.informatik.tu-muenchen.de
- Xref: senator-bedfellow.mit.edu comp.sys.amiga.introduction:9129 comp.sys.amiga.misc:118851 comp.sys.amiga.programmer:89232 comp.answers:18065 news.answers:69086
-
- Posted-By: auto-faq 2.4
- Archive-name: amiga/introduction/part1
- Last-modified: Tuesday, 9. March 1996
- Posting-Frequency: ever fourth week
-
-
- Frequently asked questions (FAQ) concerning the Amiga. [1/4]
- ------------------------------------------------------------
-
- Below you find a list of frequently asked questions. It should especially
- be for new users but perhaps experienced users may find something too.
- This is part 1, the second begins with chapter 4, the third with chapter 5,
- the fourth with chapter 7.
-
- It is in Ascii format to be easily read by everyone. It is also available
- in AmigaGuide, Dvi and html (for WWW servers) format as part of the Amiga-FAQ
- archive. (File docs/misc/AmigaFAQ.lha on any Aminet site)
-
- Please note the following:
-
- - Changes since the last posting are marked with a
- ! changed this line/section, respectively
- + added this line
- < removed something before this line
-
- - An index is at the bottom of part 4. If this still doesn't help:
- E-mail me, probably I can include an answer into the FAQ.
-
- - Suggestions, contributions, critics and beer bottles are very
- welcome. :-) Send them to:
-
- Ignaz Kellerer
- Georg-Habel-Str. 11
- 81241 Muenchen (Germany)
- Tel. (+49) 089 / 885147
-
- Internet: kellerer@informatik.tu-muenchen.de
-
- ===========================(Cut here)=========================================
-
- Amiga-FAQ
- *********
-
- This document lists some frequently asked questions and tries to
- give answers. Its intention is to help new users and to reduce the
- amount of news that most experienced users don't like to read anymore.
-
- Please notice that there are many questions that aren't answered yet,
- even more: Whole sections that remain empty! I feel that I cannot give
- satisfying answers. So it's your turn: Fill the gaps and tell me what i
- should include into this document!
-
-
- Disclaimer
-
- 1 CPU, Custom chips, RAM and other stuff
- 1 What are 68EC020, 68EC030 and 68LC040?
- 2 What's an FPU?
- 3 Can I use a 3.5' HD in my A1200?
-
- 2 The Operating System
- 1 Can I use another Kickstart than the builtin?
- 2 The Graphical User Interface
- 3 What is MUI?
- 1 Icon collections and Backgrounds
- 4 What is the Amiga equivalent of . (Current directory)?
- 5 The PIPE: queue-handler
- 1 Using PIPE: in a standard AmigaShell environment
- 2 The Pipe command
- 3 Pipe command support in AmigaShell
- 4 Quick usage guide
- 5 Related things
- 6 Troubleshooting
- 6 ARexx, the program control language
-
- 3 How about Graphics?
- 1 What are chunky and planar displays?
- 2 What is doublebuffering?
- 3 What monitors will work on my Amiga 1200/4000?
- 4 How do I switch between PAL and NTSC?
-
- 4 Programming
- 1 What documentation do I need as an Amiga programmer?
- 2 What is CATS?
- 3 Where do I get the Amiga includes?
- 4 How do I become a developer?
- 5 What compilers (assemblers) are there?
- 6 Those never working Esc sequences!
- 7 Is it possible to use AmigaBasic on the A1200?
- 8 How do I localize my program?
- 9 How to obtain a pointer to a console's window
- 10 What are pragmas?
- 11 My Compiler/Linker is complaining about missing symbol xxx.
- 12 Where do I find the function xxx?
- 13 The GNU C compiler: general information and installation
- 1 Current Version
- 2 Requirements
- 3 Authors
- 4 Sources for Gcc
- 5 Inline Headers
- 6 Amiga Libraries
- 7 Installation
- 8 Compiling
- 9 How to get help
-
- 5 Applications
- 1 Text Editors
- 2 What word processors are there?
- 3 Desktop Publishing
- 4 What is TeX and where can I get it?
- 5 Are there any Postscript interpreters?
- 1 Amiga Font Formats
- 2 Frequently Requested Amiga Fonts
- 3 Commercial Font Sources
- 4 Non-Latin fonts on the Amiga
- 5 Amiga Font Installation
- 6 Amiga Font Utilities
- 7 Making Outline Fonts
- 8 Problems and Possible Solutions
- 6 How to deal with Non-Latin texts?
- 1 Japanese editors and viewers
- 2 Chinese text viewers
-
- 6 Connecting your Amiga to the world
-
- 7 Emulators
- 1 Can I run Unix on my Amiga?
- 2 Is it possible to use the Amiga as X11 terminal?
- 3 Is there a way to start MS-Dos programs?
- 4 How to mount MsDos-formatted Syquests on Amiga
-
- 8 Miscellaneous
- 1 Is there any unix version of LhA?
- 2 What are files ending with ...?
- 3 Is there a Stacker-like utility to pack my hard drive?
- 4 Where do I get Fish disk xxx?
-
- 9 Where and how do I get software and other informations?
- 1 Files and databases on freely distributable software
- 2 A collection of tests
- 3 Getting files from a FTP server
- 4 Getting files from a Mail server
- 5 Getting files from a mailbox
- 6 The Fish PD series
- 1 The Amiga Library disks
- 2 The Fresh Fish CD-Roms
- 7 How do I Read and write MS-Dos disks?
- 8 How do I split large files?
- 9 Discussing things
- 10 Other FAQ's
-
- The Amiga-FAQ archive
-
- Contributions
-
- Credits
-
- Index
-
-
-
- Disclaimer
- **********
-
- This document is
-
- Copyright (C) Ignaz Kellerer
- Georg-Habel-Str. 11
- 81241 Munich (Germany)
- Tel. (+49) 089 / 885147
- Internet: kellerer@informatik.tu-muenchen.de
-
- Permission is granted to make and distribute verbatim and modified
- copies of this document following the terms of the "GNU General Public
- License" provided the copyright notice and this permission notice are
- preserved on all copies.
-
- The author gives *absolutely no* warranty that the answers given
- here are correct or usable. Many of them were contributed by other users
- and I cannot even make marginal checks. If you think that something
- should be changed, please tell me. Suggestions, contributions, new
- answers, critics, flames (oh, how I like this `nil:' :-) are rather
- welcome. See Contributions.
-
- 1 CPU, Custom chips, RAM and other stuff
- ****************************************
-
- This chapter contains questions concerning the Amiga-Hardware.
-
- 1.1 What are 68EC020, 68EC030 and 68LC040?
- ==========================================
-
- Motorola, the company producing the 680x0 family offers crippled
- versions of their processors. They are a little bit cheaper than the
- originals, that's why Commodore decided to build the 68EC020 into the
- A1200 and the 68EC030 into the A4000/030.
-
- The difference between the 68020 and the 68EC020 is that the latter
- can address just 16Mb of memory. That's why the A1200 cannot have more
- that 10 Mb RAM. In most cases you will not notice the difference.
-
- This is not the case for the 68EC030: Many owners will notice that
- the 68030 has an MMU and the 68EC030 doesn't have. There are some
- important programs depending on an MMU, for example Enforcer (a
- debugging utility), GigaMem (a program to emulate virtual memory) or
- all current Unix versions (see Unix). Other Amigas than the A4000 and
- the A3000 need an additional processor card using a 68030 or 68040 or
- 68060 to run these.
-
- Finally the 68LC040 is a 68040 without FPU. See FPU.
-
- 1.2 What's an FPU?
- ==================
-
- The first 680x0 processors (upto 68030) could process integers only.
- Floating point operations had to be emulated by the software. An FPU is
- a chip (or part of a chip) that can process floating point operations, a
- mathematical coprocessor.
-
- One separates three FPU types on the Amiga: The 68881, 68882 and the
- 68040's internal FPU. The 68882 is up to 1.5 times faster than the
- 68881, because it is splitted in two parts: A conversion unit (the
- FPU's are using an 80 bit format internally) and the arithmetic unit.
- The 68040's internal FPU adds a pipeline, but misses the trigonometric
- instructions of the others. These are still emulated by the software,
- 68040.library for example.
-
- Special programs (Raytracing, DTP, Mathematics, TeX) are offered in a
- special coprocessor version which are up to 50 times faster than the
- original versions.
-
- Michael Kaiser (kaiser@ira.uka.de)
-
- 1.3 Can I use a 3.5' HD in my A1200?
- ====================================
-
- Many people would prefer to use a 3.5" instead of the smaller 2.5"
- drives as the former are much cheaper. This is possible, but you need a
- special cable to connect the drive to your IDE controller. Additionally
- you should put some isolating material between the drive and the main
- board. Some people report termic problems but I did not notice anything.
-
- Some dealers offer a set which contains the cable, isolating material
- and for about 20$. See the magazines for more information.
-
- Thomas Schuh (thomas@stepout.tynet.sub.org)
-
- If you are going to install an IDE-harddisk, regardless if 2.5" or
- 3.5", you should always consider that the it may not work flawlessly,
- if the drive and ROM-version have not been tested and approved by
- Commodore. Regarding the A1200, one should also remember that this
- Amiga has not been designed to hold 3.5" harddisk drives. The 2.5"
- drives, which are mainly thought for portable computers, may have some
- advantages (for example in power consumption, heat emission or shock
- resistance) that could pay off because of the small keyboard case of
- the A1200 and the limited power supply. With the larger 3.5" drives,
- ventilation inside the computer might also be disturbed. If it is
- necessary to remove some shielding inside the A1200 to make the drive
- fit inside, even radio interference may occur.
-
- To sum it up: if 3.5" harddisk drives could really be used in the
- A1200 without any problems, you could be sure Commodore themselves
- wouldn't have used the slightly more expensive 2.5" drives in the
- A1200-HD.
-
- 2 The Operating System
- **********************
-
- This chapter handles questions concerning the operating system,
- Kickstart as well as the Workbench.
-
- 2.1 Can I use another Kickstart than the builtin?
- =================================================
-
- First let's drop some words on the Kickstart's Copyright: This
- belongs to Commodore, you *must not* use Kickstarts, without the right
- to do it! Especially it isn't allowed to make an image of anyone
- else's Kickstart and run this on your own Amiga. (I even doubt that it
- is allowed to do this on your own Amigas, if you have more than one.)
-
- But of course it is possible and allowed for some people, developers
- for example. There are two different ways, a hardware solution and a
- software solution. The former is to buy a card which can hold two or
- more Kickstart ROMS and allows to select between when the System is
- booting.
-
- The software solution needs a program (softkicker) and an image of
- the ROM. The softkicker allocates RAM, loads the ROM image into the
- allocated memory and reboots. Of course you have less RAM after the
- Reboot: 256Kb when running Kickstart 1.2 or 1.3 and 512Kb for Kickstart
- 2.0 or higher.
-
- There are different Softkickers, some of them needing a MMU (see
- 68EC0xx). I recommend SKick 3.43 (Aminet, directory `util/boot')
- because it doesn't need a MMU and supports many different Kickstarts.
- It is rather easy to create the ROM image using the following program:
-
- #include <stdio.h>
-
- #define kickorig 0xf80000 /* 0xfc0000 for Kick 1.2 und 1.3 */
- #define kicklen 0x080000 /* 0x040000 for Kick 1.2 und 1.3 */
-
- void main(int argc, char*argv[])
- {
- FILE *fh;
-
- if ((fh = fopen("kickstart.file", "w")) != NULL) {
- result = fwrite(kickorig, kicklen, 1, fh);
- }
- fclose(fh);
- }
-
- 2.2 The Graphical User Interface
- ================================
-
- Die standardmΣ▀ig mitgelieferte OberflΣche "Workbench" ist nur die
- Grundlage zum Aufbau einer guten, angenehmen OberflΣche.
-
- Zu diesem Zweck gibt es zahlreiche Tools, die den Anwendern das
- Leben erleichtern. Einige von diesem findet man auf dem Aminet in den
- Verzeichnissen `util/#?/'.
-
- 2.3 What is MUI?
- ================
-
- MUI is a set of shared libraries which are used to build a
- comfortable GUI (`Graphical user interface'). The general idea of MUI
- is that the programmer determines only the logical structure of the GUI
- and the look (Font, Size, Windows on Workbench, Public Screen, own
- Screen, ...) is determined by the user only. From the programmers point
- of view using MUI is simpler than `gadtools.library' but much more
- powerful. On the other hand MUI interfaces are slower than
- GadTools-Interfaces, especially on old 68000 machines.
-
- MUI is found in two archives, one for developers only and one for
- users. Source: Aminet, `dev/misc'.
-
- 2.3.1 Icon collections and Backgrounds
- --------------------------------------
-
- The standard icons aren't beautiful, indeed. But there do exist
- some beautiful icon collections. I know of `MagicWB' and `NewIcons'.
-
- `MagicWB' is Shareware. The icons are drawn beautiful in pastel with
- every known trick. You also get a lot of good backgrounds which
- beautify workbench windows and MUI programs. Fine and good readable
- fonts replace the clumsy topaz8 font. You also get good icons for the
- ToolManager. You can find a test version of MagicWB on Aminet.
-
- `NewIcons' is Freeware. The icons do have relative intensive colors
- and are drawn as three dimensional objects floating slanted in space.
- You can find NewIcons on Aminet, `util/wb/NewIcons.lha'.
-
- *F:*
- How do I turn off the "Gag" of MagicWorkbench (the intro which
- appears sometimes during booting)?
-
- *A:*
- In S: should be a file called `mti.data'. Delete it.
-
- *F:*
- How can I create NewIcons?
-
- *A:*
- The author of NewIcon currently works on an IconEd. Until then,
- Iconian 2.9x (I3) is the only way to create NewIcons.
-
- *F:*
- How can I prevent MagicWorkbench Icons to appear in incorrect
- colors?
-
- *A:*
- Register MagicWB 2.0, it contains a tool which patches the palette,
- or get one of the different tools from Aminet.
-
- *MagicColors*
- *ShoveColors*
- Its a good program, you can find it in Iconian, PictIcon or
- `Aminet:util/wb/').
-
- 2.4 What is the Amiga equivalent of . (Current directory)?
- ==========================================================
-
- The AmigaDOS equivalent for the . representing the current directory
- on Unix and certain non-reentrant interrupt handlers is the empty
- string, which is written as "".
-
- Example:
- COPY S:Startup-Sequence ""
-
- copies your Startup-Sequence to the current directory.
-
- There is some FD software available to patch a Unix-like
- interpretation of . and .. into the AmigaDOS, including, but not
- limited to, Martin Scott's UnixDirs. (Aminet,
- `os20/util/UnixDirsII.lha' or Fish-disk 837)
-
- Arno Eigenwillig (arno@yaps.dinoco.de)
-
- 2.5 The PIPE: queue-handler
- ===========================
-
- In the AmigaOS release 2.04, a new handler for passing data between
- programs was introduced. This handler is called `L:Queue-Handler',
- better known as the `PIPE:' device.
-
- `PIPE:' implements a true `pipe' familiar from UNIX systems. Its
- function is to pass the output of one program to another program as
- input. You can chain several programs together using multiple pipes.
-
- The advantages of using pipes are:
- 1. No need for a lot of RAM to keep the temporary files, or, no need
- to slow things down by storing temporary files on the HD.
-
- 2. Faster operation since the intermediate data doesn't need to be
- stored anywhere between programs.
-
- The `PIPE:' device differs from the UNIX pipes in two important
- respects:
- 1. It is a device, so the input and output of the programs doesn't
- need to be a redirected standard output, although that is the
- general case. You can also use `PIPE:' instead of files, with two
- restrictions; you can not read a directory from `PIPE:', and the
- `PIPE:' `file' can not be `seeked' in.
-
- 2. It does not support a flush operation. If all of the data written
- in a `PIPE:' device is not read out, it will stay there, buffered.
- Thus you must always `empty' a pipe before closing it.
-
- 3. Because of the above, if unread data exceeds the size of the
- `PIPE:' internal buffer, the program writing to the pipe will
- `block' (that is, suspend operation) until the data is read. See
- below on how to manually flush a pipe.
-
- The PIPE: handler name syntax is `PIPE:name/bufsize/bufnum', where
- `name' is the name for the pipe channel. Using names you can have
- several simultaneous pipe operations. The optional arguments
- `bufsize'and `bufnum' specify the size and number of the buffers used
- by `PIPE:'. Normally, you would just use `PIPE:name'.
-
- The default buffer size of `PIPE:' is 4096 bytes, and the number of
- buffers (ie. channels) is unlimited.
-
- Osma Ahvenlampi (Osma.Ahvenlampi@hut.fi)
-
- 2.5.1 Using PIPE: in a standard AmigaShell environment
- ------------------------------------------------------
-
- First, make sure `PIPE:' is mounted. You can do this by giving the
- command
- 1> Mount PIPE:
-
- in a Shell window. On an AmigaOS 2.1+ system, `PIPE:' is normally
- mounted on startup by placing the mount entry file `PIPE' in the drawer
- `DEVS:DosDrivers'.
-
- In an AmigaShell window, give the commands:
- 1> Run List SYS: >PIPE:Listoutput
- 1> More <PIPE:Listoutput
-
- (1)
-
- These two commands list the contents of the `SYS:' volume to a pipe
- and then type it in the Shell window. You could also use:
- 1> Run List SYS: NOHEAD >PIPE:Listoutput
- 1> Run Sort PIPE:Listoutput PIPE:Sortedoutput
- 1> More <PIPE:Sortedoutput
-
- Notice that you need to `Run' all the programs except for the last one.
- This is so that you can get them all running simultaneously. You could
- also use several Shell windows, or any other way of running all the
- programs at the same time. Also this might not work if `More' isn't the
- standard Commodore AmigaOS 2.04+ More found in `SYS:Utilities'.
-
- In case you need to manually flush a pipe, for example because the
- program that was reading from it aborts prematurely, it can be done
- with the command:
- 1> Type PIPE:name TO NIL:
-
- ---------- Footnotes ----------
-
- (1) Note that `1>' is the prompt AmigaShell gives when it is
- waiting for a command. The number varies, and the prompt can be
- customised to look completely different. It is not a part of the
- command.
-
- 2.5.2 The Pipe command
- ----------------------
-
- As you can see, this is a somewhat difficult way of using pipes,
- needing a lot of typing especially compared to the UNIX pipes. There is
- a solution for that.
-
- Andy Finkel, a former Commodore software engineer wrote a command
- called `Pipe' (not to be confused with `PIPE:') that simplifies the use
- of the `PIPE:' device. Unfortunately, this command did not make it into
- the 2.04 release. However, Commodore has given the permission to
- distribute this, and a few other commands, freely. (Sources: Fish disk
- 673, Aminet, `util/cli/finkelshelltools.lha')
-
- For some reason Commodore did not include these commands in the later
- OS releases, although they work fine even with OS 3.1 (V40). Thus all
- users are required to get them from the above sources if they wish to
- use them.
-
- The Pipe command usage is simple. The commands to be run with their
- inputs and outputs piped together are given as arguments to the
- command, separated by the | (vertical bar) character:
-
- 1> Pipe List SYS: | More
- or
- 1> Pipe List: SYS: NOHEAD | Sort IN: OUT: | More
-
- Notice how Sort needs `IN:' and `OUT:'. These devices don't actually
- exist, but the Pipe command simulates them with the PIPE:. This is
- necessary because C:Sort can not use the `standard IO', but insists on
- files.
-
- The separator character | can be configured to be something else
- with the local variable __PCHAR.
-
- 2.5.3 Pipe command support in AmigaShell
- ----------------------------------------
-
- There is a little known and quite useful undocumented feature built
- in the 2.04+ AmigaShell, that is, AmigaShell knows about the `Pipe'
- command. By setting the local variable _PCHAR, you can use pipes
- without even entering the Pipe command. AmigaShell will prepend it on
- the command line automatically if it sees the pipe separator command
- specified by _pchar on the command line.
-
- Thus, after the command:
- 1> Set _pchar "|"
-
- (1)
-
- the above examples can be used like this:
- 1> List SYS: | More
- or
- 1> List SYS: NOHEAD | Sort IN: OUT: | More
-
- Those familiar with the UNIX pipes will notice how the usage is very
- similar to the UNIX pipe usage.
-
- ---------- Footnotes ----------
-
- (1) The quotes around the vertical bar are important, to avoid
- AmigaShell interpreting the command as an attempt to use PIPE:, if
- _PCHAR is already set (for example if the Shell is started from within
- another one).
-
- 2.5.4 Quick usage guide
- -----------------------
-
- 1. Get the ShellTools archive from the Fish disk 673, or from Aminet,
- `util/cli/hacks204.lha'.
-
- 2. Install the commands in this archive in your Shell search path,
- preferably C:.
-
- 3. Put the command `Set _pchar |' in your `S:Shell-Startup' file.
-
- 4. Restart your AmigaShell so that it reads the `S:Shell-Startup'.
-
- 5. Try `List SYS: | More'
-
- 6. Read the ShellTools documentation and experiment.
-
- 2.5.5 Related things
- --------------------
-
- The variable _mchar is used to separate one command from another in
- a shell line. So, after the command:
- 1> Set _mchar ";"
- you can put more shell commands into the same line, separated from
- each other by `;'.
-
- 2.5.6 Troubleshooting
- ---------------------
-
- *Q:*
- When I try the command `List SYS: | More' I get an error
- PIPE: Unknown command
-
- I have `PIPE:' mounted, what's wrong?
-
- *A:*
- AmigaShell is referring to the command `Pipe' in the error, not the
- `PIPE:' device. You haven't installed the commands in the
- ShellTools archive.
-
- *Q:*
- I get a requester that says
- Please insert volume PIPE: in any drive
-
- when I try any of the command examples.
-
- *A:*
- `PIPE:' is not mounted. Try `Mount PIPE:'. If that doesn't work,
- refer to your AmigaDOS manual or a friend that knows how to mount
- devices.
-
- *Q:*
- When I try any of the examples the More window pops up but nothing
- is shown/I get an error afterwards/More pops up a file requester.
-
- *A:*
- You are not using the standard AmigaOS `More' command. Either use
- another name or install a command that supports pipes.
- Possibilities are the C= More, Less, or Most for example.
-
- *Q:*
- With use of PIPE:, sometimes characters get lost. What happened?
-
- *A:*
- Up to OS 3.1, the queue-handler has some bugs which don't allow a
- really foolproof transmission of data. A compatible replacement
- for the queue-handler can be founbd on Aminet,
- `util/sys/HWGQueue.lha'.
-
- *Q:*
- None of these happen but it still doesn't work as you described.
-
- *A:*
- Are you using OS 2.04 later? Are you using the standard AmigaShell?
- Try with all extras disabled.
-
- 2.6 ARexx, the program control language
- =======================================
-
- *Q:*
- I want to send an ARexx command through CLI or through a shell
- script, but that (rx ADDRESS PORTNAME;COMMAND) doesnt work.
-
- *A:*
- You have to put quotation marks. (rx "ADDRESS PORTNAME;COMMAND").
- It also prevents upcasing the portname when it should be lowercase.
-
- 3 How about Graphics?
- *********************
-
- Graphics is one of the major strengths of the Amiga. Why don't we
- have more answers here? :-(
-
- 3.1 What are chunky and planar displays?
- ========================================
-
- Simply put, the terms `chunky' and `planar' (short for `bitplanar')
- refer to different ways of storing graphics information in a computer's
- memory. They are rather easy to understand, as far as things go, but
- incredibly difficult to explain:
-
- Computer images are arranged as a grid of pixels, each of which can
- be thought of as a number representing the color number of the pixel,
- sort of like a paint-by-numbers scheme. For example, here's a
- simplified example image, in four colors:
-
- 00302132
-
- The Amiga stores this image in a `bitplane' mode. That is, it is
- represented by several planes of bits (binary digits, 1s or 0s). This
- is a four-color image, so each color number could be represented by two
- bits. Therefore there are two bitplanes:
-
- 00100110 Here's bitplane 0
- 00101011 And here's bitplane 1
- -------- Now, let's add them up, binary style:
- 00302132
-
- Which is the final image. If the image was in two dimensions, it
- would truly be composed of bit planes. However, I'd need three
- dimensions to show multiple bitplanes overlayed, and therefore for
- simplicity we're working in one dimension (which is all we need).
-
- Now, there's another way of storing this image. How about if we
- localize the bit data in little chunks?
-
- 00 00 11 00 01 10 11 01 = 00302132
-
- This is the principle of the `chunky' pixel mode.
-
- Both methods of image storage are perfectly logical, and no one can
- say that one is better than the other. However, there are certain
- technical aspects which cause certain advantages and disadvantages.
-
- First, if you've seen colored text scroll on your Amiga, you know
- there is a bit of "flicker" that arises. Specifically, what happens is
- that while the text is scrolling, its color temporarily changes to
- something completely different. What's happening is that the computer's
- moving several bitplanes of data while the raster (monitor electron
- gun) is sweeping across the screen. What that means is that, if the
- raster catches the data while it's being moved, you can end up with some
- bitplanes being moved and some not. What if we filled bitplane 1 in the
- example above with 0s? Instantly all the 3s become 1s, and the 2s
- become 0s! This is what causes "flicker" when certain colors are
- scrolled. By contrast, if a chunky pixel display is caught while
- scrolling, all we see is a partially-scrolled image; the colors are
- preserved (since their units are the small ones).
-
- That's a disadvantage to planar pixels, but what about chunky pixels?
- Well, recall that a computer organizes information in terms of 8 bit
- bytes. These groups are static; you cannot decide to all of a sudden
- organize data in terms of three bytes or something! Therefore, when
- using chunky pixels, things get complicated if we decide to use a
- nonconvenient number of bits per pixel. In practice, the 8-bit
- (256-color) mode, and 24-bit (16 million color) modes are the most
- common candidates for chunky pixel displays.
-
- Finally, certain effects can be accomplished with the different
- systems. Bitplanar mode is particularly useful for things like shadows
- (where an extra bitplane is set with 1s instead of 0s), and chunky mode
- is great for perspective and "mapping" (since the data for each pixel is
- localized in a single "chunk"). The latter advantage makes chunky pixel
- mode really great for games, and is what made Wolfenstein 3-D possible.
-
- We all know that Amigas use the bitplane system for storing images.
- However, the Macintosh and PC(VGA) both use chunky pixel modes. While
- we can optimize our RAM usage with "bizarre" modes like 8- and
- 128-color, they gain the advantages of non-flicker scrolling, and the
- programming simplicity of just writing a byte where you want the pixel
- to go.
-
- The difference between the two modes becomes problematic in things
- like emulation. EMPLANT has a "chunky to planar" routine which it uses
- to convert a Macintosh display into an Amiga one. "Chunky to planar"
- routines are also useful for getting chunky-inclined things to run on
- Amigas (see TMAPDemo, rotdemo). On a side note, there was some
- confusion as to what EMPLANT used the MMU for with regard to chunky to
- planar. The MMU itself is incapable of performing the algorithm for the
- conversion; rather, it is used to detect what portions of the display
- memory are updated from the Mac side, and therefore the processor is
- saved from having to perform the chunky to planar conversion for the
- entire display.
-
- I sincerely hope that helped clear up most of the mystery concerning
- the terms "Chunky" and "Planar"!
-
- (Joseph Luk, jluc@eis.calstate.edu)
-
- 3.2 What is doublebuffering?
- ============================
-
- Don't be ashamed if you haven't a clue as to what this is. It's
- rather simple, really. Imagine you wanted to animate something by
- drawing out each frame. Now imagine you had only one piece of paper.
- Even if you drew pretty fast, it would be difficult to see what the
- animation looks like because you'd have to erase the frame you just
- drew, in order to draw the next one!
-
- What if you had two pieces of paper? Why, then, you could see the
- difference between two adjacent frames. First you'd draw your first
- frame on the first piece of paper, then you'd draw the second frame on
- the other piece. Then you'd erase the picture on the first piece of
- paper, and draw in the third frame. Then you'd erase the picture on the
- second piece of paper, and draw in the fourth frame, and so forth.
-
- This is the principle of doublebuffering. The computer shows you the
- picture it just drew, then turns around and draws the next one. It then
- swaps the picture in front of you with the one it just drew, and
- repeats the process. The result is a smooth animation, because you
- never need to see the computer draw; all you see is each finished
- product.
-
- (Joseph Luk, jluc@eis.calstate.edu)
-
- 3.3 What monitors will work on my Amiga 1200/4000?
- ==================================================
-
- Monitors can be classified after the horizontal scan frequency they
- require. TVs, as well as C='s 1084 monitor, need frequencies around 15
- kHz. VGA/SVGA need approx. 30 kHz. Multisync monitors can take many
- frequencies.
-
- In short: You can use any monitor you want with an A1200. BUT:
-
- - If you use a regular VGA/SVGA monitor, you can only use a few
- display modes (like DblPAL, DblNTSC and/or Productivity). I.e.
- (320|640) x (256|512|1024) for DblPAL. This is great for Workbench
- and all "serious" utilities (DTP etc), but don't expect any games
- to work... they don't use your preferences, just take over the
- machine and assume a 15 kHz monitor. Also, you cannot utilize the
- "Early Startup Control" screen (you know, disable cache, and that
- stuff), which also requires a 15 kHz monitor. Furthermore, VGA
- monitors don't have speakers. And the VGA-type modes don't support
- Genlocks. But for a lot of "serious" work, a VGA monitor is quite
- adequate.
-
- - You already know what happens with a 15 kHz monitor; the
- flickering in Interlace mode. A small tip: Try to use NTSC instead
- of PAL. This increases the refresh rate from 25 Hz to 30 Hz, at
- the expense of lower vertical resolution (482 lines maximum). The
- NTSC and PAL modes aren't as bad as many people think. If your
- monitor has a lot of phosphorous (long afterglow), PAL Laced can
- be quite OK, and it gives you a resolution of 1448x566 in
- SuperHiRes. That's the highest resolution currently supported on
- AGA Amigas, in _any_ display mode.
-
- - A Multisync gives you the best of both worlds. The 1940 and 1942
- monitors from C= are quite OK, although rather cumbersome to
- use... The h/v size and offset must be set manually each time you
- switch display mode. (1) The 1960 monitor doesn't have this
- problem, but it's a bit more expensive.
-
- For a VGA/SVGA or Multisync monitor, you'd need a little shiny box
- which gives you the standard 15-pin "D" connector. It costs around $15.
-
- There are other alternatives... like the "AmiVGA" box ($50 or so),
- which I think is a cheapo version of the Flicker Fixer. (But it's
- really a shame to use this on an AGA Amiga.)
-
- Also, you can get a VGA monitor, and hook up your TV to the
- composite or RF port on the Amiga - one monitor for games, one for
- serious stuff.
-
- (Per Espen Hagen, per.e.hagen@ffi.no)
-
- ---------- Footnotes ----------
-
- (1) A patch is available on Aminet for Kickstart 3.0 to do this
- without manual actions in the file `os30/util/Monitor30Patch.lha'.
-
- 3.4 How do I switch between PAL and NTSC?
- =========================================
-
- PAL and NTSC are two different video standards, the former being
- European, and the latter being American. PAL has a slightly taller
- screen (256 lines non-interlaced, non-overscanned) as opposed to NTSC
- (200 lines), so if you see the bottom portion of a program's screen
- getting cut off on your American machine, chances are the program was
- written for PAL, and is running on your shorter NTSC screen. PAL and
- NTSC differences are somewhat less important to European users; since
- their machines default to PAL, running an NTSC program is no more than
- a minor annoyance having the screen only appear in the top portion of
- the display.
-
- Therefore, for us NTSC folks, switching into PAL mode becomes
- important to avoid loss of some picture on Euro Demos, etc.
-
- First, the most common misconception about switching between PAL and
- NTSC is that you need a Multiscan or special monitor for such a purpose.
- Not so! Just about any monitor can handle the minor signal difference
- between PAL and NTSC (50Hz vertical refresh versus 60Hz). The 108x,
- 19xx, and 20xx series, and even most TVs, can display both PAL and NTSC.
- Sometimes it is necessary to perform minor tweaking of vertical hold
- and/or v. size on your monitor to achieve full display, though this is
- trivial.
-
- What IS needed to switch between PAL and NTSC in software, is a
- "Fatter" (1MB) Agnus or better. If your system has more than 512K of
- CHIP RAM (use the avail command to find out) you have this chip. If you
- do not, ou can still construct a hardware switch (see below).
-
- The following directions assume you're an NTSC user who wants to
- switch into PAL mode, but the procedure for going from PAL to NTSC is
- much the same.
-
- The most common use of switching into PAL is for self-booting games,
- demos, etc. The best way to accomplish this on pre-3.0 systems is to
- use Chris Hames' Degrader program (most recent version: 1.30). Once you
- have procured this program, the switch is as simple as selecting
- "50Hz", and "50Hz System", then installing the program's ROMTag (little
- program that runs at boot-time) by pressing the "Survive Reset(s)"
- button.
-
- AmigaDOS 3.0 added a PAL/NTSC switch feature to its Boot Menu, and
- all you need to do in order to access this is hold down both mouse
- buttons as the computer boots. Select Display Options, Display
- Mode/PAL, and then Boot. If the program still fails to go into PAL mode
- (Zool is one I've found), you may wish to get Degrader anyway and try
- that.
-
- Software PAL/NTSC switching is easy and painless. Some people have
- gone even further by installing hardware PAL/NTSC switches. This
- results in a system which even the most nasty hardware-banging programs
- can't bring to its original configuration (if it has been switched).
- The procedure is simple - most Amigas have jumpers already - but beyond
- the scope of this document.
-
- Therefore, if your screen is too short or cut off, seek the different
- screen mode. You'll "see new horizons", literally!
-
- (Joseph Luk, jluc@eis.calstate.edu)
-
- (1)
-
- ---------- Footnotes ----------
-
- (1) PAL/NTSC switching with a MultiSync monitor is possible on 2.0+
- and easily accomplished by moving the PAL monitor type to (or NTSC, as
- applicable, I have them both in) the Devs/Monitors drawer (from the
- Storage/Monitors drawer), reboot, then go into the Prefs drawer and
- select the ScreenMode program. You will see at least two PAL modes
- available (PAL and PAL Interlaced). Simply select one of the (usually
- non-interlaced for demos) and select "Use". All windows on the Workbench
- will close, the video mode will change, and then the windows will
- reopen - that simple!
-
- Allen J. Newton, anewton@alturia.abq.nm.us
-
-