[malko]

Originally Posted by lifeschool

[...]
1. I made a RAD disk the other day but when I reset the emulator with a software reset command, the RAD disappeared. Is this meant to happen or is there a way to preserve it? Do TSRs work? [...]

Here is what are saying some books from BitD :

From AmigaDOS Inside and Out (1991 - Abacus - Kerkloh, Tornsdorf & Zoller)

[...] Workbench 1.3 implementation:
[...] RAD: A recoverable RAM disk. Unlike the device ram:, data remains in
memory even after the computer is reset. Not even a Guru Meditation
can reset the RAD: device. Unfortunately, memory management is not
dynamic, so RAD: takes up all of its allotted memory even when it is
empty. The capacity of RAD: is included in the MountList.
[...] 3.9 The RAD device (RAD: )
Workbench 1.3 implementation:
The abbreviation RAD stands for Recoverable RAm Disk. This is a
reset-resistant RAM disk for the Amiga. The RAM disk device named
ram: loses all of its information after a reset A normal reset does not
affect the rad: device. In most cases the data can even survive a Guru
Meditation. The ramdrive. device is located in the Devs :
directory.
The rad: device has at least one disadvantage. RAD doesn't have a
dynamic memory system. RAD uses the same amount of memory
whether it contains any data in it or not. A typical entry for the RAD:
device in the Mount List looks like the following:
..... RAD: Device = ramdrive.device
..... Unit = 0
..... Flags = 0
..... Surfaces = 2
..... BlocksPerTrack = 11
..... Reserved = 2
..... Interleave = 0
..... LowCyl = 0
..... HighCyl =21
..... Buffers = 5
..... BufMemType = 1
..... #
You must specify RAD's capacity in the HighCyl parameter before
you can mount RAD with mount rad:. Each cylinder has a capacity
of 1 IK. RAD would have a capacity of (21+1) * 1 IK = 242K if it were
mounted using the above entry. In 1.3 RAD must be formatted before
it can be used with the FastFileSystem.
After a reset, all you have to do is enter mount rad: and the contents
of RAD are restored. If you discover that some data is lost, use the
diskdoctor to restore RAD.
When RAD is no longer needed, the largest section of its memory can
be freed by using the remrad command. It can be removed by using
the ASSIGN command:
ASSIGN RAD: REMOVE
The entire memory area that was occupied by RAD is then free after the
next boot operation. [...]

From Amiga best tricks tips (1989 - Abacus - Bleek, Weltner & Maelger)

[...] 13.4.2 FFS and recoverable RAM disk
The RAM disk RAD: can also work with the FastFileSystem.
However, rad : becomes non-resistant to resets when used with FFS
(data on this disk disappears following a reset). The memory
conservation and speed factor alone are reasons enough to use RAD: for
many applications. But the possibility always exists that the RAM
disk could be wiped out. You'll need to change the name and Unit
arguments of the RAD: Mount list. Use the next highest number to
avoid any overlap. The corresponding Mount list entry may look like
the following:
..... FRAD: Device = ramdrive.device
..... FileSystem = L:FastFileSystem
..... Unit = 1 /* Number of the RAM-Disk */
..... Flags = 0
..... Surfaces = 2
..... BlocksPerTrack = 11
..... Reserved = 2
..... Interleave = 0
..... Mount = 1
..... LowCyl = 0
..... DosType = 0x444F5301
..... HighCyl = 79 /* Available RAM <512K->5)*/
..... Buffers = 22 /* ditto */
..... BufMemType = 1 /* Same as where it lies */
..... #
You must insert the following in the startup sequence:
MOUNT FRAD:
FORMAT >NIL: <NIL: DRIVE FRAD: NAME "FSS in RAM"
The nil device supports both redirection commands. The first
suppresses any output, while the second suppresses any requesters
asking you to insert a disk in RAM. If you work with programs which
allow you to choose between DFO to DF3, we recommend that the
original name be given in the Mount list. The drive must be placed in
the startup sequence in place of frad if the original device is desired.
[...]

From Amiga disk and drives insider guide (1994 - BSB - Overaa)

[...] The RAD Disk
Since release 1 .3 AmigaDOS has also
provided something called a recoverable
Ram Disk - the RAD: device. Unlike the
conventional Amiga Ram Disk, RAD: is not automatically created by
the system and, with recent releases of the operating system, to acti
vate it you must either double click on the RAD icon in the
Storage/DOSDrivers drawer or, if you always want one, drag the RAD
icon to the DEVS/DOSDrivers drawer. The default instance of this
device nowadays appears as the icon RAM_O.
The primary advantage of a RAD Disk is that the device and its con
tents are able to recover from various system mishaps. It can survive a
reboot and, in many cases, will survive a software failure as well.
Unlike the Ram Disk, however, RAD: does not automatically adjust its
memory use according to the files being stored in it. Instead its size is
pre-set by the Mountlist entry nowadays stored in the DOSDrivers
RAD file. The default High Cyl (high cylinder) value of 79 produces a
RAD Disk with the same capacity as a conventional Amiga floppy,
880k. To change the size of the RAD unit it is only necessary to change
the HighCyl value in the Mountlist. Any number of RAD: devices, all
with different names and sizes, can be set up by creating new
Mountlist entries.
As with the conventional Ram Disk, RAD: can be used to hold copies
of frequently used commands and so on. Many programmers find a
RAD Disk invaluable for safeguarding important files during those
precarious first stages of program development. It is even possible to
duplicate the Workbench S directory and Startup-Sequence in order to
be able to reboot from the RAD Disk in the event of a software failure.
This again is useful for coders working with machines that do not
have a hard disk since it greatly speeds up the reboot procedure. Users
with hard disk machines do not have to worry as far as reboot times
are concern ed because rebooting from hard disk is relatively fast any
way. [...]