Unwanted automatic lowmem-reserving

Grex · 30 December 2020, 20:27

Both, the exec.library V45 from OS 3.9 BB2 and Harry Sintonens Exec V44 will automatically reserve the lowmem (as required e.g. by Fusion or Shapeshifter). I always wondered if this is actually essential for these exec-versions to work, or if it is just a little bonus-feature (that could be removed, at least in theory).
I have installed several rom-updates on my Amiga and I would also like to try one of these updated exec-libraries, but I know from my experience with Fusions "Rsrv..."-programs, that a reserved lowmem will stop certain old/badly coded games and demos from working correctly. Hence I would prefer not having my lowmem reserved all the time...
So, is there anything, I (as an experienced vanilla-user) can do, to use a newer exec and still get rid somehow of the automatic lowmem reserving?

Thomas Richter · 31 December 2020, 12:13

A little bit of research would have answered that:

http://aminet.net/package/util/boot/MoveLow

That means, in the FAQ of 3.1.4.

Grex · 31 December 2020, 20:47

I don't have Os 3.1.4 (maybe somedays). I am using Os 3.9.
So this doesn't really answer my question, it just says, that I can't use your tool to solve my problem - if it is solvable at all.
I just wanted to know (which is exactely what I have written), if Exec44 or Exec45 are really dependant on the lowmem being reserved, for their own operation, or if this is just some extra-feature. In the latter case, MAYBE an experienced amiga-coder (and there are many on EAB) could easily write a patch, to remove this (unwanted) feature from the module-file.

If I would want permanent low-mem-reservation, this wouldn't be a problem for me in the first place, because I have the KickFlash-Card by Individual-Computers. The actually only real purpose of such a card (there are cards with similar functions from Elbox and E3b) is to avoid the additional reboot on power-on or hardreset. So I wouldn't appreciate this automatic reservation-feature, as it would give me no benefit, only (compatibility) problems.

And whenever I use "Boot with no Startup-Sequence" from the Early-Boot-Menu (which I do quite often, for troubleshooting or degrading), I want my system to be as naked and unaltered as possible, which I think is reasonable. A few rom-updates and fixes most likely won't hurt here, but the reserving would.

Grex · 14 January 2021, 19:34

Strange. After installing Exec 45 I noticed that, according to "ShowConfig", my Chipram will beginn (as intended by Exec 45) at $4000 ONLY after power-on or hardreset. However after every normal reset it is shown to start at $1000 (as usual on 68040).
Even though I guess this is a bug, it kind of solves the problem for me.

Thomas Richter · 16 January 2021, 16:21

Low-memory reservation is done very early during bootstrap. This requires ROM support to work reliably.

Grex · 16 January 2021, 20:02

I guess it is hence also impossible to ever get low-mem-reserving when you use LoadModule to install Exec V45, as a hardreset would kill all modules installed by programs of this kind.

By the way, could you explain the term "bootstrap", please? I have read this term a couple of times, but I don't know what it means.

30 December 2020, 20:27	#1
Grex Registered User Join Date: May 2007 Location: Austria Posts: 67	Unwanted automatic lowmem-reserving Both, the exec.library V45 from OS 3.9 BB2 and Harry Sintonens Exec V44 will automatically reserve the lowmem (as required e.g. by Fusion or Shapeshifter). I always wondered if this is actually essential for these exec-versions to work, or if it is just a little bonus-feature (that could be removed, at least in theory). I have installed several rom-updates on my Amiga and I would also like to try one of these updated exec-libraries, but I know from my experience with Fusions "Rsrv..."-programs, that a reserved lowmem will stop certain old/badly coded games and demos from working correctly. Hence I would prefer not having my lowmem reserved all the time... So, is there anything, I (as an experienced vanilla-user) can do, to use a newer exec and still get rid somehow of the automatic lowmem reserving?

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31 December 2020, 12:13	#2
Thomas Richter Registered User Join Date: Jan 2019 Location: Germany Posts: 3,251	A little bit of research would have answered that: http://aminet.net/package/util/boot/MoveLow That means, in the FAQ of 3.1.4.

31 December 2020, 20:47	#3
Grex Registered User Join Date: May 2007 Location: Austria Posts: 67	I don't have Os 3.1.4 (maybe somedays). I am using Os 3.9. So this doesn't really answer my question, it just says, that I can't use your tool to solve my problem - if it is solvable at all. I just wanted to know (which is exactely what I have written), if Exec44 or Exec45 are really dependant on the lowmem being reserved, for their own operation, or if this is just some extra-feature. In the latter case, MAYBE an experienced amiga-coder (and there are many on EAB) could easily write a patch, to remove this (unwanted) feature from the module-file. If I would want permanent low-mem-reservation, this wouldn't be a problem for me in the first place, because I have the KickFlash-Card by Individual-Computers. The actually only real purpose of such a card (there are cards with similar functions from Elbox and E3b) is to avoid the additional reboot on power-on or hardreset. So I wouldn't appreciate this automatic reservation-feature, as it would give me no benefit, only (compatibility) problems. And whenever I use "Boot with no Startup-Sequence" from the Early-Boot-Menu (which I do quite often, for troubleshooting or degrading), I want my system to be as naked and unaltered as possible, which I think is reasonable. A few rom-updates and fixes most likely won't hurt here, but the reserving would.

14 January 2021, 19:34	#4
Grex Registered User Join Date: May 2007 Location: Austria Posts: 67	Strange. After installing Exec 45 I noticed that, according to "ShowConfig", my Chipram will beginn (as intended by Exec 45) at $4000 ONLY after power-on or hardreset. However after every normal reset it is shown to start at $1000 (as usual on 68040). Even though I guess this is a bug, it kind of solves the problem for me.

16 January 2021, 16:21	#5
Thomas Richter Registered User Join Date: Jan 2019 Location: Germany Posts: 3,251	Low-memory reservation is done very early during bootstrap. This requires ROM support to work reliably.

16 January 2021, 20:02	#6
Grex Registered User Join Date: May 2007 Location: Austria Posts: 67	I guess it is hence also impossible to ever get low-mem-reserving when you use LoadModule to install Exec V45, as a hardreset would kill all modules installed by programs of this kind. By the way, could you explain the term "bootstrap", please? I have read this term a couple of times, but I don't know what it means.

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