Can't do save file on thumbnail drive

[bigpup]

Finally the clue as to what is causing the issue.

On purpose, the save process is designed to offer to place the save on the drive Puppy is on and booting from.
That drive has to always be mounted, because it mounts to boot from it.
Thus the save is always accessible.
Puppy does not auto mount drives.

The only install that is different is a live install to a CD/DVD.
The CD/DVD is usually formatted iso9660 (that is read only) after Puppy is installed to it, Cannot write to it anymore.
So when making a save for a running Puppy on a CD/DVD.
The save has to be placed on a drive that you can write to.
Normally it looks for the computers internal drive as place to put the save. That drive is read/write.
Well, any drive that is type that can read/write.

The boot menu config file entry pmedia= is used by the boot process to identify what type drive booting from.
This affects some of the Puppy processes operations, based on type of drive.
pmedia=cd
pmedia=usbflash (usb flash drive)
pmedia=atahd
pmedia=ataflash (internal flash memory type drive)

Try this:
Change the pmedia= in the boot loader menu config file entry to pmedia=cd.
Boot using this entry.
Do not already be using a save. Need to boot not using a save.
Have the USB drive plugged in and mount it by clicking on it's desktop drive icon.
Shutdown.
When asked about making a save.
Does it now offer the USB as a choice?

Note:
If the save is now on the USB.
Not sure what would happen, finding the save at boot, if more than this one USB drive is plugged in.

[wizard]

@Lassar

SEE EDIT

This works for me.

-boot xenial from hdd with no save file
-plug in the usb and note the identifier
-open grub.cfg in geany
-add this switch to the end of the kernel line: psave=identifier

example usb = sdb1:
linux /vmlinuz pfix=fsck pmedia=cd psave=sdb1

-reboot

Now when you shutdown the save file will be created in sdb1

EDIT - the save file is created, unfortunately, Puppy does not find it on reboot because the USB is not mounted.

wizard

[bigpup]

Yes, that may also work.
However that is assuming the USB drive will always be seen as sdb1.
With only one internal drive and one USB drive plugged in, it should be sdb1.
However, I have seen this not always be true, if the computer has multiple drives.

You also need to have a pmedia= entry.
This affects how the save is used and saved to.

[rcrsn51]

EDIT - the save file is created, unfortunately, Puppy does not find it on reboot because the USB is not mounted.

FWIW, Porteus booting can do this easily. You can boot off one drive and specify the location of the changes folder on another.

[wizard]

@rcrsn51

Thought maybe it could be done with grub2 grub-mount command.

The program grub-mount performs a read-only mount of any file system or file system image that GRUB understands, using GRUB’s file system drivers via FUSE. (It is only available if FUSE development files were present when GRUB was built.)

My test setup has xenial64 on hdd and used grub2config to add the grub2 bootloader. Inserted "grub-mount /dev/sdb1 /mnt" into grub.cfg, but when booting got error message that grub-mount was not found.

wizard

[rcrsn51]

I don't think that this is an issue of what grub4dos/grub2 can do. Their only job is to find and load the vmlinuz and initrd.gz files.

It's the job of the initrd to manage the savefile mechanism. IIRC, old Puppies had more flexibility on where the save was located.

I suspect that the new rules require that the save be on the same drive as the main sfs files. You can select a different partition as long as it's on the same drive.

Someone with more knowledge of how the initrd works can clarify this.