@ -596,6 +596,14 @@ technique is useful when:
The RAM disk and ROM disk drives will be available even if you have
no physical disk devices attached to your system.
Booting an operating system from ROM is not intended as a way to use
your operating system on a long-term basis. The ROM disk has only
a small subset of the operating system files. Additionally, you
cannot easily customize your ROM disk because you cannot write to it.
For any significant use of an operating system, you should boot directly
to the disk/slice that contains the complete operating system. This
is described in the next section.
## Starting Operating Systems from Disk
In order to make use of the more sophisticated operating systems
@ -619,7 +627,7 @@ has been assigned to the disk and slice you selected to boot.
If you receive the error message "Disk not bootable!", you have
either failed to properly initialize the disk and slice requested
or you have selected the wrong disk/slice.
or you have selected an invalid/unavailable disk/slice.
The following example shows a disk boot into the first slice of disk
unit 4 which happens to be the CP/M 2.2 operating system on this disk.
@ -697,6 +705,26 @@ have specified. It does not know what operating system is at that
location. The layout of operating systems on disk media is described in
the Using Disks section of this document.
### Auto-Submit Batch Files
All of the operating systems supplied with RomWBW have the ability to
execute a "batch" of commands by creating a batch submission file
containing the commands to be executed. The specifics of using
batch files in a specific operating system is covered in its specific
documentation.
At boot, the operating system will look for a specific batch file
(`PROFILE.SUB` for CP/M 2.2 and 3) on the boot drive and execute that
batch file automatically. This allows you to automatically customize
your operating system with any commands desired at boot. CP/M 2.2 did
not originally have the ability to automatically excute a batch file at
boot, but the CBIOS in RomWBW has added this capability.
Since RomWBW can utilize many disk slices, it is very easy to create
slices for specific workflows (editing, software development, games,
etc.). You can then just boot to the slice that is optimized for the
task you want to perform.
## System Management
### Listing Disk Device Inventory
@ -902,7 +930,7 @@ Configuring Drives...
```
You will probably see more drive letters than this. The drive letter
assignment process is described below in the Drive Letter Assignment
assignment process is described below in the [ Drive Letter Assignment]
section. Be aware that RomWBW will only assign drive letters to disk
interfaces that actually have media in them. If you do not see drive
letters assigned as expected, refer to the prior system boot messages
@ -993,6 +1021,69 @@ rest of the drive letters will be offset to accommodate this. This is
done because most legacy operating systems expect that A: will be the
boot drive.
### Default Drive Letter Assignment
As shown above, when an operating system is booted, RomWBW will
automatically assign drive letters to physical disk devices. The
assignment process varies depending on: 1) the drive/slice you choose to
boot from, and 2) the number and type of physical drives in your
system.
If you boot an operating system from ROM, then the first two drive
letters will be assigned to your RAM disk (A:) and your ROM disk (B:).
It may seem odd that the RAM disk is assigned to A: in this case. The
reason for this is to accommodate certain functions that require that A:
be a writable disk drive. For example, A: **must** be writable in order
to submit batch files.
If you boot to a physical disk device, then the first drive letter (A:)
will be assigned to the disk/slice that you chose to boot from. The A:
drive letter is considered special by most operating systems and is
automatically used in some cases. By making the selected disk/slice the
A: drive, you can setup different disks/slices for specific uses and
just boot to it.
After the first drive letter is assigned (as well as the second drive
letter in the case of a ROM boot), RomWBW will assign additional drive
letters based on the disk drives in the system. Additional drive
letters will be assigned in the following order:
- RAM Disk
- ROM Disk
- Floppy Disk(s)
- Hard Disk(s)
If a disk/slice was already assigned as the A: (or B:) drive letter,
then it will not be assigned again.
In the case of floppy, RAM, and ROM disks, a single drive letter will be
assigned to each physical disk (even if there is no disk media in the
drive).
In the case of hard disks, 1-8 drive letters will be assigned to the
initial 1-8 slices of the disk drive. The number of drive letters
assigned to each hard disk depends on the number of hard disks in the
system:
- 1 Hard Disk: 8 drive letters (slices)
- 2 Hard Disks: 4 drive letters (slices) per disk
- 3+ Hard Disks: 2 drive letters (slices) per disk
This somewhat complicated algorithm is used to try and maximize the
limited number of operating system drive letters available (16) to
the available disk devices as evenly as possible.
Note that for hard disk devices, drive letters will only be assigned
to disk devices that actually contain media. So, for example, if you
have an SD Card slot in your system, but it has no SD Card inserted, then
no drive letters will be assigned to it.
Since drive letter assignments are easily changed at any time using the
`ASSIGN` command, you can customize your assignments as desired after
starting the operating system. Even better, you can use an auto-submit
batch file to customzie the assignments at startup without any user
intervention.
## ROM & RAM Disks
A typical RomWBW system has 512KB of ROM and 512KB of RAM. Some
Wayne Warthen
2 years ago