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Author Topic: IRQ-loading - would this be possible on the EP? (Read 2022 times)

Online gflorez

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Re: IRQ-loading - would this be possible on the EP?
« Reply #30 on: 2017.April.18. 15:57:15 »
You come, say that of "upcoming EPNET network card" and leave so calm....

Now I am getting a terrible desire to have some sort of Bus expansion card...

Offline BruceTanner

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Re: IRQ-loading - would this be possible on the EP?
« Reply #31 on: 2017.April.18. 18:03:05 »
You come, say that of "upcoming EPNET network card" and leave so calm....

Now I am getting a terrible desire to have some sort of Bus expansion card...

I decided to re-spin the EPNET PCB before I let any out into the world (sorry for further delay though). I am hoping the new one will be able to sit between the EP and other expansion, and it will also have 512k RAM and a compact FLASH socket. So no expansion card normally needed :ds_icon_cheesygrin:

Online gflorez

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Re: IRQ-loading - would this be possible on the EP?
« Reply #32 on: 2017.April.18. 18:51:42 »
Very good idea. Just like the Spectrum add-ons.

Offline Sdw

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Re: IRQ-loading - would this be possible on the EP?
« Reply #33 on: 2017.April.18. 22:01:32 »
Thanks for testing!

Especially to BruceTanner for giving it a go on real disk! Is it a 3.5" 720kb drive?

As I suspected, it seems like it is too slow. If we are really lucky, it's only the initial seek that is slow, and the rest of the load is faster.
I've made a new version now, where all pictures are put into one binary, perhaps it will improve the situation somewhat?

If possible, could you give this new version a try as well? I would really appreciate it!

Note that since this one just does a seek at the beginning, it only cycles through the pictures once, so after the picture of the womans face nothing more happens.

Offline Zozosoft

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Re: IRQ-loading - would this be possible on the EP?
« Reply #34 on: 2017.April.18. 23:02:38 »
It is still crazy slow on floppy :oops: I also tried real 8 sectored format (bigger GAPs between the sectors), but it is don't help.
10MHz also don't help :-(

Offline Sdw

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Re: IRQ-loading - would this be possible on the EP?
« Reply #35 on: 2017.April.18. 23:06:29 »
Thanks for testing!

Seems like I have to abandon my dream of a large multiload Enterprise demo, unless I set SD-card interface as a requirement. :/

Offline Zozosoft

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Re: IRQ-loading - would this be possible on the EP?
« Reply #36 on: 2017.April.18. 23:17:36 »
Many-many years ago I also tried floppy+music, the near to acceptable combination are using direct diskio, on real 8 sectored disk. Probably more better possible with special formated disk (for example using 256 bytes sector size, and/or less sectors. Using sliding sector numbering for avoid wait at track change.)

More easy idea: small animation with Nick chip during the loading. It is not need any CPU time.

Offline IstvanV

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Re: IRQ-loading - would this be possible on the EP?
« Reply #37 on: 2017.April.19. 09:28:59 »
Probably more better possible with special formated disk (for example using 256 bytes sector size, and/or less sectors. Using sliding sector numbering for avoid wait at track change.)

There are actually demos on the CPC that use similar tricks with 128 bytes per sector. If a single sector can be loaded in much shorter time than one frame, then it is possible to implement the reading between interrupts. There will be errors (data lost) in some of the sectors, but the program can just try reading them again (it is more efficient to read the remaining sectors on the track first, and then retry those that failed).

The test with all the pictures can also be compressed into a single .com file (< 48K), although a full demo would probably require a separate loader:
* loadtest.com (47.74 kB - downloaded 41 times.)

Edit: reordering the image data allows for reducing the compressed size by more than 3K:
* loadtst3.com (44.44 kB - downloaded 39 times.)
« Last Edit: 2017.April.21. 09:56:21 by IstvanV »

Offline Sdw

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Re: IRQ-loading - would this be possible on the EP?
« Reply #38 on: 2017.April.19. 13:35:51 »
The problem with doing some special-formatted disk is (I think this was discussed earlier in the thread as well) that it severely limits the audience of the demo, as from the already few EP128 owners, even fewer would have that exact setup.
Not to mention that my own setup is with SD-card, so I would have no way of testing it, so that's a no-go.

Turning off the music (and perhaps displaying something with LPTs only) while easy, is simply not going to cut it for todays demowatching audience. A continuous show with music running all the time is the standard.

I'll have to consider how the acceptance for a demo which demands a modern piece of hardware (SD-card interface) would be, or just put the project to sleep altogether. One mitigating factor could perhaps be that it *will* run even on slower old disk interfaces, but the music will ofcourse be disrupted and sound bad while loading.

Approximately how long did the each picture load take when running from disk?

Offline Zozosoft

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Re: IRQ-loading - would this be possible on the EP?
« Reply #39 on: 2017.April.20. 08:23:26 »
I think the most of current Enterprise users use SD card (or hard disk) on real machine or ep128emu.
Then I think will be good if the programs add extra features when fast storage available. For example the load music :-)

Quote
Approximately how long did the each picture load take when running from disk?
This small blocks reading are very slow (because the disk rotating the sectors not continuosl readed, always need to wait next).

Offline Sdw

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Re: IRQ-loading - would this be possible on the EP?
« Reply #40 on: 2017.April.21. 14:13:33 »
I think the most of current Enterprise users use SD card (or hard disk) on real machine or ep128emu.
Then I think will be good if the programs add extra features when fast storage available. For example the load music :-)
This small blocks reading are very slow (because the disk rotating the sectors not continuosl readed, always need to wait next).

I wonder if a hard disk would be fast enough? Because IDE drives were available in the early 90ies at least, so if it would work on such a steup, it could still qualify as somewhat "period correct"...

Offline ergoGnomik

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Re: IRQ-loading - would this be possible on the EP?
« Reply #41 on: 2017.April.21. 15:39:01 »
I wonder if a hard disk would be fast enough? Because IDE drives were available in the early 90ies at least, so if it would work on such a steup, it could still qualify as somewhat "period correct"...
If I were you, I'd do it like the 8-bit Atari guys. You see, there was already available an EXDOS card with 512kB memory expansion in '88. The 256kB modification to the internal memory expansion board was available in early '92. And a 1MB expander was documented at the beginning of '94. These are all "period correct" options. (576/640kB, 320kB, 1088/1152kB RAM) Load everything in one go and decompress the necessary parts as the demo progresses. Aim for a 320kB machine as default. Use normal loading without music as fallback for unexpanded machines.

Offline Sdw

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Re: IRQ-loading - would this be possible on the EP?
« Reply #42 on: 2017.April.21. 20:30:06 »
Well, my primary target will be the system I have myself, a standard 128kb EP128 with an SD-card adapter. I had some hope that there would be a way to find an "old" config that could run the demo properly as well, to be a bit more historically accurate.
There is no way to configure those EXDOS RAM expansions to work as a RAM-drive? that way the loads would be really quick, quicker than SD-card even, but using the same code.
I really don't feel like writing a completely separate demo for RAM-expanded computers that loads everything at the beginning and the copies from extended RAM runtime instead of loading.

Offline geco

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Re: IRQ-loading - would this be possible on the EP?
« Reply #43 on: 2017.April.21. 20:45:27 »
There is no way to configure those EXDOS RAM expansions to work as a RAM-drive? that way the loads would be really quick, quicker than SD-card even, but using the same code.
It is possible, using RAMDISK :)
Just everything should be loaded into the ramdisk before starting the demo

Offline Sdw

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Re: IRQ-loading - would this be possible on the EP?
« Reply #44 on: 2017.April.22. 00:07:19 »
It is possible, using RAMDISK :)
Just everything should be loaded into the ramdisk before starting the demo

Cool! That would be awesome, then there would at least theoretically exist a way for 1988 machine to run the demo.
Is there a way that I can configure this in ep128emu and test it? (RAMDISK option)