Subj : Re: Browser tabs
To   : Spectre
From : boraxman
Date : Thu Mar 31 2022 22:59:28

 Sp>  Ar> If you use a big ramdisk, you have less RAM for doing actual computin
 Sp> 
 Sp> While that's true, the original statement seemed to be, I ran out of
 Sp> memory because I filled tha RAM drive.  That doesn't make much sense to
 Sp> me, once you create the volume the RAM is already allocated, full or
 Sp> empty shouldn't make much difference... Of course I might the memory
 Sp> allocation theory wrong... and its done dynamically... but that seems...
 Sp> dangerous and unlikely to me.

With Linux, you have three ram backed pseudo-devices.  There is /dev/ramX, which is a fixed size block device.  It is not ready to be used as a disk, as it is just a block device, you need to format it first.

There is ramfs, which is a ram based drive, and tmpfs, which is very similar. These operate in a similar manner to the Linux filesystem cache.  You can mount a filesystem of type ramfs or tmpfs and use them immediately and use their own filesystem type which is POSIX-like.  Ramfs is older, and exists solely in RAM.  By default, I believe it had no limit by default, and it couldn't be swapped out, so you could fill your RAM.  Tmpfs has a mount option to limit the size (it by default limits its to 50% physical RAM) and it can be swapped out.

Some Linux systems will use tmpfs for /tmp, but I generally also mount another tmpfs drive under /mnt/tempfs as a temporary scratch space.

Using ramfs in the old days, without specifing an upper limits could result in you leaving very very little physical RAM for the rest of your systems operations.

--- Mystic BBS v1.12 A47 2021/12/24 (Linux/64)
 * Origin: Agency BBS | Dunedin, New Zealand | agency.bbs.nz (21:1/101)

.