Big ram disc

I managed to set a 3GB ram disc but the free space only goes up to 2GB.
Also to get the Ram disc to be set on Boot up I had to run ChangeDynamicArea twice in DiscSetup.

ChangeDynamicArea -RamFsSize 524288K
ChangeDynamicArea -RamFsSize 2097152K

Apart from that it seems to work OK.

I managed to set a 3GB ram disc

I only managed 928MB.

Also to get the Ram disc to be set on Boot up I had to run ChangeDynamicArea twice in DiscSetup.

But that did setup straight away at boot.

4GB RPi4B.

Nice bit of progress, many thanks.

Probably needs to register to something like Free64 instead of Free.

Nice bit of progress

Is this something new in RISC OS 5.28? I can get a 508Mbyte Ramdisc0 on my 1Gb Iyonix now.
I set my RamDisc inside Resources.!Scrap.!Run, otherwise it isn’t available early enough.

 
IconSprites <Obey$Dir>.Themes.!Sprites
| Activate the RAMFS first!!
ChangeDynamicArea -RamFsSize 524288K
If "<Boot$ReadOnly>" = "" Then SetEval Boot$ReadOnly 0
| If Boot$ReadOnly Then CDir <Boot$ChoicesRW>.^.Scrap
| If Boot$ReadOnly Then Set Scrap$Dir <Boot$ChoicesRW>.^.Scrap Else Set Scrap$Dir <Obey$Dir>
Run <Obey$Dir>.!RunImage RAM::RamDisc0.$
If Boot$ReadOnly Then CDir <Boot$ChoicesRW>.^.Scrap Else CDir <Wimp$ScrapDir>.Scrap
If Boot$ReadOnly Then Set Scrap$Dir <Boot$ChoicesRW>.^.Scrap Else Set Scrap$Dir <Wimp$ScrapDir>.Scrap

| Note: Programs such as Netsurf and Messenger look for persistant Scrap data.

Is this something new in RISC OS 5.28? I can get a 508Mbyte Ramdisc0 on my 1Gb Iyonix now.

There are two different things. The 508MB RamDisc has been around for a while now, sizes larger than that are currently under development with the sources on git.

I only managed 928MB.

It’s defined in RiscOS.Sources.Kernel.s.ChangeDyn.

We would need a few Jeffrey to make the Ramdisc running in the other 4GB of a 8GB Pi4 :)

I only managed 928MB.

It’s defined in RiscOS.Sources.Kernel.s.ChangeDyn.

Found it, just search for 928.

I can configure a 3GB RAM disc but configuring 2048k and above results in no RAM disc at all at start up. Less that 2048k is OK.

but configuring 2048k and above results in no RAM disc at all at start up

Workaround is to manually edit DiscSetup and define it twice. The first one creates it. The second can then extend it to 2GB.

ChangeDynamicArea -RamFsSize 524288K
ChangeDynamicArea -RamFsSize 2097152K

Using a build of the latest Long Descriptor source and the Big RAM source on an 8GB RPi4 I can get a 4GB RAM disc with a drag in the Task Manager. (The Free space and Configuration tools both max out at 2048MB.)

Only briefly tested!

Note that although you can make the RAM disc DA bigger than 2GB, the filesystem will only use up to 2GB. There are a few other bits which need fixing for >2GB to work (and a few more for >4GB), so the first set of changes to get merged are likely to add support for sizes up to 2GB, and support for the larger sizes will come later.

https://gitlab.riscosopen.org/RiscOS/Sources/FileSys/RAMFS/RAMFS/-/merge_requests/3#note_2741

Using today’s v2.29 ROM, the bigger RAM disc works a treat for me. Before boot it was 518MB: After boot it was immediately 600M (which is where it had been configured). As I ‘only’ have 2GB memory I can cause other things to run out of memory if I go too high, but I have had no problems with the larger sizes.

Congratulations and thanks to Julie and others who have experimented, implemented or tested this.