tj@castle.ed.ac.uk (T Jones) (07/19/90)
A recent posting (sorry, no reference for it) said it was possible to access the wasted 0.5mb ban of RAM on a 2.5mb ST. Could someone please post more details (or email me) on how to do this. How complex are the hardware mods needed, and what special components are required. On a related note, could some kind soul please post the hardware mods to an SM 124/5 monitor needed to make OVERSCAN work. ttfn, Tomsk "Now, you dont expect the university to let me express their opinions, do you?" (Tom Jones, Meteorology Dept, Edinburgh University, SCOTLAND) (email JANET:tomsk@uk.ac.edinburgh WORLD:tomsk@edinburgh.ac.uk)
jeroen@plato.phil.ruu.nl (Jeroen Scheerder) (07/20/90)
In article <5223@castle.ed.ac.uk>, tj@castle.ed.ac.uk (T Jones) writes: |> |> A recent posting (sorry, no reference for it) said it was |>possible to access the wasted 0.5mb ban of RAM on a 2.5mb ST. |>Could someone please post more details (or email me) on how to do |>this. How complex are the hardware mods needed, and what |>special components are required. |> |> On a related note, could some kind soul please post the |>hardware mods to an SM 124/5 monitor needed to make OVERSCAN |>work. I was the one posting about the 3.0 Mb modification; however, having read the article that explaining it all (it's from a German magazine, I think it's called 'ST Magazin' or something) I decided I would let someone more experienced should do the work for me. Looking in my computer I see 2 SIMMs, and a *LOT* of wire. The overscan modification is a similar story; it's tricky, and it's all in GERMA trying to describe any of these in english, but I do not think *ANYONE* should try to change their ST based on MY description of a german artic about Math can almost be as satisfying as the real thing, and not half so risky." cf. 'The Bluffer's Guide to Bluffing'
jensting@rimfaxe.diku.dk (Jens Tingleff) (07/23/90)
jeroen@plato.phil.ruu.nl (Jeroen Scheerder) writes: >In article <5223@castle.ed.ac.uk>, tj@castle.ed.ac.uk (T Jones) writes: [..] >I was the one posting about the 3.0 Mb modification; however, having read the >article that explaining it all (it's from a German magazine, I think it's >called 'ST Magazin' or something) I decided I would let someone more experienced >should do the work for me. >Looking in my computer I see 2 SIMMs, and a *LOT* of wire. I, for one, doubt that you are *at all* able to make the ST use 3.0 MB. There are two banks of memory, each wth either 0.5 MB or 2.0MB. That makes 0.5 MB 1x0.5 1.0 MB 2x0.5 2.0 MB 1x2.0 2.5 MB 1x0.5 + 1x2.0 Not available from Atari ... 4.0 MB 2x2.0 The above calculation is based on the fact that the MMU knows about two banks, NO MORE. the nice thing ( ;-) ) is that the MMU autodetects.. . So, no unused 0.5 MB in a 2.5MB installation, no 3.0 MB installation possible. Disclaimer This may not be true for STEs, I don't know.. . Do correct me if I'm wrong. *IF* I'm wrong, please give a reference to the relevant article.. . (I have seen ads for 5.0MB extensions, where the last 1 MB was used for RAM disk, so perhaps....) Jens Jens Tingleff MSc EE, Institute of Computer Science, Copenhagen University Snail mail: DIKU Universitetsparken 1 DK2100 KBH O "It never runs around here; it just comes crashing down" apologies to Dire Straits
muts@fysaj.fys.ruu.nl (Peter Mutsaers /100000) (07/23/90)
jensting@rimfaxe.diku.dk (Jens Tingleff) writes: >*IF* I'm wrong, please give a reference to the relevant article.. . >(I have seen ads for 5.0MB extensions, where the last 1 MB was >used for RAM disk, so perhaps....) I would be interested in this possibility, does anyone know if this is true, and if so, where 5.0MB extensions are available? (in Europe) -- Peter Mutsaers email: muts@fysaj.fys.ruu.nl Rijksuniversiteit Utrecht nmutsaer@ruunsa.fys.ruu.nl Princetonplein 5 tel: (+31)-(0)30-534504 3584 CG Utrecht, Netherlands
jensting@skinfaxe.diku.dk (Jens Tingleff) (07/25/90)
muts@fysaj.fys.ruu.nl (Peter Mutsaers /100000) writes: >jensting@rimfaxe.diku.dk (Jens Tingleff) writes: >>*IF* I'm wrong, please give a reference to the relevant article.. . >>(I have seen ads for 5.0MB extensions, where the last 1 MB was >>used for RAM disk, so perhaps....) >I would be interested in this possibility, >does anyone know if this is true, and if so, where 5.0MB extensions >are available? (in Europe) Here goes: Text (my translation..) from ad "The circuits for 2.5 and 4 MB are ysable on any ST. 520+ (+) and 1040 types can be expanded to 3, 4.5 and 5 MB, of that 2.5 or 4 MB is main storage (i.e. TOS memory), and the rest is used as RAM disk. Basically, the MMU and shifter must be socketed, otherwise the computer must be converted by us. All Mega 1s must be handled by us. Please state computer type and year of manufacture when ordering" (+) The 520+ is a european breed (?) with a full megabyte installed from Atari. Price list empty PCB, 2.5 & 4 MB 259 DM empty PCB, 3 4.5 & 5 MB 348 DM RAM to 2.5 MB 744DM RAM to 4.0 MB 1396DM RAM to 3.0 MB 823 DM RAM to 4.5 MB 1478 DM RAM to 5.0 MB 1478 MB (I guess that the `RAM to' prices are including PCB.. The price difference seems to indicate that). Address Gengtec TeichStrasse 20 D-4020 Mettmann Tel: 02104/22936 Source for all this ST Magazin 6/Juni 90 page 109 Disclaimer : I know nooothing (see the relevant episode of Faulty Towers for pronounciation..). Jens Jens Tingleff MSc EE, Institute of Computer Science, Copenhagen University Snail mail: DIKU Universitetsparken 1 DK2100 KBH O "It never runs around here; it just comes crashing down" apologies to Dire Straits
piet@cs.ruu.nl (Piet van Oostrum) (07/27/90)
Please note that I am not the author of the following article. The author had some problems posting, so I did it for him. Replies should be made to: jeroen@phil.ruu.nl (Jeroen Scheerder) Due to manifold requests (since my original posting was badly formatted - I usually post things from xrn, which apparently has a weird editor) this article is reposted in an edited version. This article is a general introduction, technical details of the matter are now posted to the ..tech newsgroup, along with the schematics. In article <1990Jul23.135351.4486@diku.dk>, jensting@rimfaxe.diku.dk (Jens Tingleff) writes: |> |>I, for one, doubt that you are *at all* able to make the ST use 3.0 MB. There |>are two banks of memory, each wth either 0.5 MB or 2.0MB. That makes |> |> 0.5 MB 1x0.5 |> 1.0 MB 2x0.5 |> 2.0 MB 1x2.0 |> 2.5 MB 1x0.5 + 1x2.0 Not available from Atari ... |> 4.0 MB 2x2.0 |> |>The above calculation is based on the fact that the MMU knows about |>two banks, NO MORE. the nice thing ( ;-) ) is that the MMU autodetects.. . |> |>So, no unused 0.5 MB in a 2.5MB installation, no 3.0 MB installation |>possible. |> |>*IF* I'm wrong, please give a reference to the relevant article.. . |>(I have seen ads for 5.0MB extensions, where the last 1 MB was |>used for RAM disk, so perhaps....) |> |> Jens Yes - you *ARE* wrong. First: all those people who used to have 2 banks of 0.5 Mb, and who upgraded to 2.5 Mb have 'switched off' one of the 0.5 banks in order to be able to use this bank for 1 Mbit chips, thus creating a 2.0 Mb bank. Totally expanding a 1 Mb ST with 2 Mb gives you a 2.5 Mb ST, and one unused 0.5 Mb bank. Article: "Aus zweieinhalb mach drei", by K.-D. Litteck, in ST Computer 3/1990 (published by Heim Fachverlag in Germany). (plus: a correction to the schematic in this article in the same magazine, issue 4/1990). Now using the inactive 0.5 Mb thus resulting in a total of 3.0 Mb is possible too; it really is a hack to get around the 2 bank limit. I will describe how this is done in the article series in the ...tech newsgroup. Enjoy! Jeroen.