Amiga questions you've always been too embarrassed to ask

[Daedalus]

Yeah, it's quite a clever way of doing it - the chip RAM on the 3000 has both a 16-bit and a 32-bit bus, with some arbitration logic to glue it all together. IIRC, the 3000 has the fastest chip RAM CPU access of any Amiga model as a result.

[rabidgerry]

What is an "Assign"?

Why do I need them/what are they for?

My own uninformed theory would be, is it some kind of pretend drive the allows you to say map to it in a script or something without having to type the whole file path to where something actually exists?

[NLS]

Originally Posted by rabidgerry

What is an "Assign"?

Why do I need them/what are they for?

My own uninformed theory would be, is it some kind of pretend drive the allows you to say map to it in a script or something without having to type the whole file path to where something actually exists?

Roughly yes.
https://wiki.amigaos.net/wiki/AmigaO...ference#ASSIGN

[Foebane]

I have one:

Are Amiga sprites vertically limited to a low resolution?

Like, horizontally, you can have lo-res, all the way up to super hi-res in AGA, but the vertical resolution always remains the same, like no interlace in the sprites?

[Thomas Richter]

Originally Posted by Foebane

Are Amiga sprites vertically limited to a low resolution?

No. You can load new sprite data every other frame, i.e. alternate the sprite data, and thus get single-line resolution. It is just more work.



Horizontally, sprites on ECS are limited to 140ns on Low-Res and Hi-Res screens, and to 70ns on SuperHires screens.


Vertically, they are limited to one line, or two lines on Interlace if you do not reload the sprite data.


On AGA, the horizontal resolution can be set, and sprites can be additionally doubled vertically.


Thus, of course you can do interlace in the sprites, just nobody likes interlace in first place.

[Foebane]

Thomas, know of any examples of interlaced sprites? I'd love to see one. Even on WinUAE, I'd be able to spot them.

[rabidgerry]

Originally Posted by NLS

Roughly yes.
https://wiki.amigaos.net/wiki/AmigaO...ference#ASSIGN

Thanks

[MAN-biker]

Hello, guys.
Can anybody help me with Scalos?
I have a question:

is it possible to make a normal run .info files in TEXT-view?
If i run a WHDLoad game, for example, in ICON-view by clicking on game icon - it runs normally.
But if I try to run this .info file in TEXT-view, it bring me "Execute a File" window to how I want to run this .info file.
How I can automate\tune SCALOS to run .info files in TEXT-view like it runs in ICON-view one?

P.S.: without scalos all works fine in any view mode, so it's a Scalos' sh*t.

[MrClump]

I don’t think this one has been asked.

Just what is it that Amigas are doing to their floppy drives to make them sound so distinctive? I know the drives are essentially mechanically the same as PC drives. But while PC floppies generally tick quietly along, Amigas often sound like they’re trying to shear the disk in two!

[Daedalus]

Short answer: the head stepping speed is different.

Slightly longer answer: head stepping is relatively simple - a pulse from the computer tells the head stepper motor to move one step forwards or backwards. This is a relatively sudden movement and creates a noise as a result. Stringing lots of steps together one after another results in a vibration, which is what you hear when the heads seek, the tone of which changes with the frequency of the step pulses.

Most mechanisms based on stepper motors like this will have certain movement speeds which are quieter, and certain speeds which are louder, and it's part of the design process to deal with these (or at least, it *should* be). The stepping speed is fixed on PC-style floppy controllers, and it's likely that drives are optimised to be quietest at this speed. On the Amiga however, the head seek speed is determined by software, and thus changes based on conditions. CPU load can cause a slower and noisier seek, for example, and custom trackloaders used by games and demos might use less-than-optimal speeds, causing excessive vibration and resonance, resulting in louder, harsher seek sounds.

[Foebane]

Originally Posted by Daedalus

Most mechanisms based on stepper motors like this will have certain movement speeds which are quieter, and certain speeds which are louder, and it's part of the design process to deal with these (or at least, it *should* be). The stepping speed is fixed on PC-style floppy controllers, and it's likely that drives are optimised to be quietest at this speed. On the Amiga however, the head seek speed is determined by software, and thus changes based on conditions. CPU load can cause a slower and noisier seek, for example, and custom trackloaders used by games and demos might use less-than-optimal speeds, causing excessive vibration and resonance, resulting in louder, harsher seek sounds.

This is fascinating, but the sound is less than pleasant, especially if it's heard over demo music or game action, and it baffles me to this day WHY WinUAE would include floppy drive sounds: at least they can be turned OFF. What really IRKS ME is those YouTube videos of Demoscene productions that actually have floppy drive sounds embedded IN them!! I want to hear the MUSIC, not the grinding of a stepper motor!!

[Thomas Richter]

Originally Posted by MrClump

Just what is it that Amigas are doing to their floppy drives to make them sound so distinctive?

Timing is troublesome, in particular in a multitasking operating system. Whenever a task comes in the way, processor time is stolen from the trackdisk.device performing a wait for the next step, and then next step is delayed - for example by the input device queying the mouse and the keyboard. This makes the whole process irregular, giving an unpleasant sound.

[NLS]

What people above said, PLUS that exactly having a multi-tasking system, allows for two processes to access the same device. In the case of floppy (and when a batch file is running in a multiple-process setup - using the run command for example), it jumps in two places (or more), trying to complete each process individually in its time share. Thus, WAY more jumping.

Also I would say Amiga floppies were usually more fragmented and they lacked index (so more seeks).

WinUAE OF COURSE implements this because it was part of Amiga "character" and a nostalgia factor.
Plus there were at least a couple of demos that utilized the sound made from the floppy.
(and these also work well in WinUAE)

[MrClump]

Originally Posted by Daedalus

Short answer: the head stepping speed is different.

Slightly longer answer: head stepping is relatively simple - a pulse from the computer tells the head stepper motor to move one step forwards or backwards. This is a relatively sudden movement and creates a noise as a result. Stringing lots of steps together one after another results in a vibration, which is what you hear when the heads seek, the tone of which changes with the frequency of the step pulses.

Most mechanisms based on stepper motors like this will have certain movement speeds which are quieter, and certain speeds which are louder, and it's part of the design process to deal with these (or at least, it *should* be). The stepping speed is fixed on PC-style floppy controllers, and it's likely that drives are optimised to be quietest at this speed. On the Amiga however, the head seek speed is determined by software, and thus changes based on conditions. CPU load can cause a slower and noisier seek, for example, and custom trackloaders used by games and demos might use less-than-optimal speeds, causing excessive vibration and resonance, resulting in louder, harsher seek sounds.

Fascinating, I never thought it would be something like that! Thank you for giving such a great answer to my question.

[MrClump]

Originally Posted by Foebane

This is fascinating, but the sound is less than pleasant, especially if it's heard over demo music or game action

Agreed! Yet when I installed a Gotek I found the complete silence a little disconcerting and ended up installing a piezo beeper within a few days!

[Predseda]

Search YouTube for Floppotron.

[Thomas Richter]

Originally Posted by NLS

What people above said, PLUS that exactly having a multi-tasking system, allows for two processes to access the same device. In the case of floppy (and when a batch file is running in a multiple-process setup - using the run command for example), it jumps in two places (or more), trying to complete each process individually in its time share. Thus, WAY more jumping.

There is much more about this... it is of course not the trackdisk.device here, but the FFS which does the disk gronking. While the FFS uses multiple parallel coroutines to get its work done, it does not attempt to re-order read accesses that reach the FFS. Each read is a new request which is handled sequentially.

The shell contains a particular logic to reduce the problem a bit by delaying the shell that initiated a "run" until the initiated command is loaded and launched. This was different in 1.3 where "run" returned immediately to its caller and then caused a lot more gronking.

[NLS]

Originally Posted by Thomas Richter

There is much more about this... it is of course not the trackdisk.device here, but the FFS which does the disk gronking. While the FFS uses multiple parallel coroutines to get its work done, it does not attempt to re-order read accesses that reach the FFS. Each read is a new request which is handled sequentially.

The shell contains a particular logic to reduce the problem a bit by delaying the shell that initiated a "run" until the initiated command is loaded and launched. This was different in 1.3 where "run" returned immediately to its caller and then caused a lot more gronking.

[MrClump]

Originally Posted by Thomas Richter

The shell contains a particular logic to reduce the problem a bit by delaying the shell that initiated a "run" until the initiated command is loaded and launched. This was different in 1.3 where "run" returned immediately to its caller and then caused a lot more gronking.

Sounds almost like the opposite of modern spinning rust drives where they have algorithms to re-order reads to minimise head movement.

[Akiko]

So many moons ago I used to have a PicassoIV with Paloma TV, and Concierto sound module. As far as I can recall it was possible to use use the Concierto independently of the Picasso, meaning I could have another graphics card installed without using the Picasso RTG. I'm just curious would it also possible to use the Paloma TV card independently, could you have something like a ZZ9000 graphics card and use the Paloma together? I'm guessing not but just asking.