Manual selection of extended memory banks in some demos

[Gunstar]

There are a few demos that won't normally load and work on my Rambo (compatible) 512K upgrade, but allow manual entry of extended memory banks for "non-standard" upgrades. Anyway, I'm more than happy to select the proper memory locations/banks if I knew the hexidecimal locations, I don't.

 

Can anyone list for me, the hex codes for extended memory banks for a Rambo with 512K.

Edited March 7, 2012 by Gunstar

[Rybags]

How many banks does it want?

I think they only do this for the benefit of those who want to preserve Dos or Ramdisk contents. Given the demo then has to use a table containing "valid" bank numbers, they could do it automatically anyway. Some should bypass and do so if you just hit Return.

 

You could try just supplying the default 130XE banks. Should be:

E3, E7, EB, EF

 

Those values assume CPU bit set, OS on, Basic off.

 

If more banking numbers are required, try the same lower nybble, but with different high nybbles.

A? turns off bit 6 which should provide another 4 banks.

 

If seperate Antic banking isn't available then bit 5 becomes available, giving more possibilities.

Some schemes use bit 7 (1 Meg only?) - IIRC you also need bit 1=0 in those cases.

[Gunstar]

The particular demo I'm planning on selecting memory banks for right now is asking for 12 extended banks or 192K extended memory, basically the original Rambo's 192K of X-ram. But I thought I'd like to know all the banks upto 512K or 448K of X-ram for future reference. No seperate Antic banking available. Below is a picture with the memory banks possible to select, I need those for Rambo extended ram.

Edited March 7, 2012 by Gunstar

[Rybags]

Mem-Test v1.0 (1996)(Jaku-B)(Pl).atr

 

There's a few utilities about, this one you just boot and it gives a list of banks you have available.

[Gunstar]

Thanks. I think I tried this one before when I had 256K and it said I have more than that. I tried it again (pic below) and it tells me I have 3 more banks than I do, 560K. I'd love it if I had an extra 48K, but I know I only have 16x256K chips in there...the problem being, which 3 banks showing aren't really there?

Edited March 7, 2012 by Gunstar

[Rybags]

I'd suspect that your upgrade is one that remaps main RAM with some banking combos.

 

Looks like this particular memtest doesn't cater for that, you'd not really want those banks to be used for extended Ram.

 

There's other threads and uploads of memory testers around, I thought I had one handy but that's all I could find.

[Rybags]

SYSTEST.ATR

 

This might work better.

 

LOAD XRAM021.COM from the Dos prompt.

[Gunstar]

Thanks, Xram worked. I found out my problem, apparently I have a bad chip. In the picture below, I should have a memory bank at $87 which doesn't show up and $83 comes up as a bad memory bank in testing. I think these are both on the same chip.

So, 31 banks are showing instead of 32, and one that's showing is bad, so I have 30 banks of working memory.

[Fox-1 / mnx]

Does this help?

 

from: http://www.faqs.org/faqs/atari-8-bit/faq/

 

 

- Size: 512k / 02468ACE (total = 576k RAM, 32 banks)

- Banks: 3, 7, B, F

- Blocks: 02468ACE = 8 blocks * 4 banks

- Types: 1) upgrade / combination of 26AE and 8ACE RAMdisk

types to 512k RAM or into *one* 02468ACE RAMdisk;

idea by me, built by Bernhard Pahl

2) Upgrade of the Rambo XL to 512k by Dan Schmid

(see Pooldisk Too, Subdir ACE/ Acec202a.ATR and

Acec202b.ATR) and of course 3) self-made RAMdisks...

3) 512k SRAM upgrade by Bernd Herale, available

from mega-hz, Wolfram Fischer

[+CharlieChaplin]

Does this help?

 

from: http://www.faqs.org/...tari-8-bit/faq/

 

 

- Size: 512k / 02468ACE (total = 576k RAM, 32 banks)

- Banks: 3, 7, B, F

- Blocks: 02468ACE = 8 blocks * 4 banks

- Types: 1) upgrade / combination of 26AE and 8ACE RAMdisk

types to 512k RAM or into *one* 02468ACE RAMdisk;

idea by me, built by Bernhard Pahl

2) Upgrade of the Rambo XL to 512k by Dan Schmid

(see Pooldisk Too, Subdir ACE/ Acec202a.ATR and

Acec202b.ATR) and of course 3) self-made RAMdisks...

3) 512k SRAM upgrade by Bernd Herale, available

from mega-hz, Wolfram Fischer

 

 

Hmm,

 

it looks like Gunstar has a Rambo 512k, where 64k base RAM is replaced with 512k RAM, thus he now has 64k base RAM and 448k extra RAM. Now you may say, hey - the information in the FAQ is also wrong then, problem is, I don`t have a Rambo enhancement and I never had one. Various Atarians reported to me that their Rambo was simply replacing 64k base RAM with 256k or 512k RAM (total memory = 256k or 512k RAM), while others reported to me they still had their 64k base RAM and added 256k or 512k RAM (total memory = 320k or 576k RAM). I do not know for sure what is correct for Rambo type enhancements.

 

Maybe a) the original versions by ICD only replaced 64k RAM by xyzk RAM and b) then there were also so-called Rambo-compatible upgrades that added xyzk RAM to the base RAM ?!?

 

As said before, Gunstar`s RAM enhancement behaves like a typical "replace 64k base RAM with xyz kbytes RAM" enhancement and therefore shows this typical behaviour. All ramdisk test programs I know will not test this kind of enhancement correctly and will not show all available / all correct rambanks. Think I have asked several times if one could not program a test-utility just for these kind of RAM enhancements, but I always got the response, that this is a hardware issue that cannot be solved in software (and as a non-programmer I have to live with that)...

 

Quote from the A8FAQ (section 8.10):

XRAM minus 64k Base-RAM:

 

- Size: 192k / 8AE (total = 256k RAM, usable = 12 banks)

- Banks: 3, 7, B, F

- Blocks: 8AE, = 3 blocks * 4 banks

- Types: older Newell RAMdisks (replace 64k by 256k);

 

- Size: 192k / ACE (total = 256k RAM, usable = 12 banks)

- Banks: 3, 7, B, F

- Blocks: ACE, = 3 blocks * 4 banks

- Types: newer Newell RDs, newer Buchholz-RDs, ICD

Rambo-XL with 256k RAM, self-made RAMdisks

(replace 64k by 256k)...

 

- Size: 448k / 2468ACE (total = 512k, usable = 28 banks)

- Banks: 3, 7, B, F

- Blocks: 2468ACE, = 7 blocks * 4 banks

- Types: ICD Rambo-XL with 512k RAM ?, self-made Ramdisks

(replace 64k by 512k)...

 

- Size: 896k? / 0248ACE (total = 1024k, usable = 56 banks)

- Banks: 1, 3, 5, 7, 9, B, D, F

- Blocks: 0248ACE = 7 blocks * 8 banks

- Types: Bob Woolley`s 1200XL 1MB Upgrade, self-made RDs

(replace 64k by 1024k)...

 

Although these RAM upgrades are relatively easy to build

(and to install into the computer), they make problems with

quite some software. Some programs tend to use the base RAM

as extra RAM / RAMdisk with these upgrades, which will most

often result in a crash of the computer. Next, most extra RAM

testers will show more extra RAM (or a bigger RAMdisk) than

there is really available (e.g. with a 256k upgrade you will

see 240k extra RAM, but there is only 64k base RAM + 192k

extra RAM). Alas, this is a typical hardware problem for these

upgrades and it cannot be solved or avoided with software...

 

Anyways, the A8FAQ also mentions dozens of demos, games and tools and how they have to be setup (or which ramdisk banks must be available) for use with extra RAM in section 8.11 and 8.12... e.g. in a lot of older polish demos, one has to hold down the SHIFT key while booting to get to the setup, then choose or type-in your rambanks there...

 

-Andreas Koch.

Edited March 7, 2012 by CharlieChaplin

[+CharlieChaplin]

[double-post]

Edited March 7, 2012 by CharlieChaplin

[Gunstar]

Rambo and compatible upgrades generally have a total of 256K or 512K memory (192K or 448K extended). Yes, the original 8x64K chips are replaced with 8x256K chips and another 8x256K piggy-back for a total of 448K exteneded ram or 512K total. So Charliechaplin is spot on.

 

I'm guessing my ram is all working correctly, and Xram is just not working correctly, show 31 banks, of which only 30 showing as "OK" and total memory of 496K is just wrong.

 

I'd like to try something that uses more than 320K and less than 512K that is NTSC compatible to know for sure though...I've got demos that are 320K and one possibly that's 576K, some 320K like NUMEN work fine, some don't, but I think that's PAL related.

Edited March 7, 2012 by Gunstar

[+CharlieChaplin]

Well,

 

I do not know of any demos/games/tools (apps) that require more than 320k RAM, but less than 576k RAM. Anyways, these should be your available extra rambanks Gunstar:

 

EXTENDED MEMORY BANKS:

 

EF EB E7 E3 CF CB C7 C3

AF AB A7 A3 8F 8B 87 83

6F 6B 67 63 4F 4B 47 43

2F 2B 27 23

 

Bits used of Port B - 765432

 

As said before, there are also lots of Rambo compatible enhancements, that *add* 256k RAM to the existing 64k base RAM (for example the european RAM enhancements from Atari Magazin and TOMS, they have 320k total memory). Greetings, Andreas Koch.

Edited March 7, 2012 by CharlieChaplin

[Rybags]

The problem (remapping main) can be detected and solved, but probably a case of most demos either being hardcoded or not doing thourough testing.

 

I'm midway through a detection routine for another purpose. The method I have in mind is:

 

- switch PortB to each possible value in $00-$FC order. Write that value to locations $4004 and $7FF0, preserving "previous" contents in a buffer in main Ram.

 

- Set PortB to $FE, write zeros to locations 4, $3FF0, $4004, $7FF0, $8004, $BFF0, $C004, $FFF0 to invalidate possible main memory remappings.

 

- build a table of extended banks using PortB value stepping from $FC back to $00. A valid bank is indicated by the PortB value appearing in $4004 and $7FF0. For valid banks, restore saved "previous" values from buffer.

Edited March 7, 2012 by Rybags

[Gunstar]

Well,

 

I do not know of any demos/games/tools (apps) that require more than 320k RAM, but less than 576k RAM. Anyways, these should be your available extra rambanks Gunstar:

 

EXTENDED MEMORY BANKS:

 

EF EB E7 E3 CF CB C7 C3

AF AB A7 A3 8F 8B 87 83

6F 6B 67 63 4F 4B 47 43

2F 2B 27 23

 

Bits used of Port B - 765432

 

As said before, there are also lots of Rambo compatible enhancements, that *add* 256k RAM to the existing 64k base RAM (for example the european RAM enhancements from Atari Magazin and TOMS, they have 320k total memory). Greetings, Andreas Koch.

 

I suppose the same thing could be done with a Rambo upgrade, leaving the original 64K chips in there and adding 256K chips on top, The original Rambo instructions just called for replacing the 64K with 256K chips, and never even suggested expansion by piggy-back.

 

that's a homebrew add-on (I think by Bob Wooley) to the Rambo.

 

I guess they figured why settle for 320K in piggy-back when you can do 512K instead? (any more than 2 high won't fit under the case)

You could also probably use a Rambo or compatible (Atarimax) upgrade to just piggy-back 64K chips giving 128K like the XE, but again, why bother when you can have 512K.

 

A 576K upgrade could probably be done using the Rambo type upgrade too, you would have to create a seperate board though, piggy-back style wouldn't fit in the XL's.

 

The XE line has the advantage of two rows of ram chips allowing 64K to remain and then add in 256/512K on the other row.

 

Oh, and thanks for the memory locations!

Edited March 8, 2012 by Gunstar

[Gunstar]

The problem (remapping main) can be detected and solved, but probably a case of most demos either being hardcoded or not doing thourough testing.

 

I'm midway through a detection routine for another purpose. The method I have in mind is:

 

- switch PortB to each possible value in $00-$FC order. Write that value to locations $4004 and $7FF0, preserving "previous" contents in a buffer in main Ram.

 

- Set PortB to $FE, write zeros to locations 4, $3FF0, $4004, $7FF0, $8004, $BFF0, $C004, $FFF0 to invalidate possible main memory remappings.

 

- build a table of extended banks using PortB value stepping from $FC back to $00. A valid bank is indicated by the PortB value appearing in $4004 and $7FF0. For valid banks, restore saved "previous" values from buffer.

 

Sounds great. I'd love to test your little detection routine if you can make it into an executable file or maybe Spartados batch file.

[Rybags]

It's half baked. It was in aid of the next version of the AtrLoad system which itself is kinda on hold since last year.

 

Doesn't yet eliminate duplicated main Ram banking, and isn't interactive in any way, just generates a table in memory.