Hardware manual

5. The Executive
The Alto Executive is itself a subsystem and lives on the file Executive.Run; if you don’t like it, you can
write your own. It is currently invoked from scratch after the operating system is booted, and whenever a
subsystem returns. The Executive is fully documented in the "Alto Subsystems" manual.
6. Operating Procedures
6.1. Installing the operating system
The "Install" command causes the operating system to execute special code which completely initializes
the system. The options of the install procedure are controlled by prompts. Installation is needed:
- When a new version of the operating system is distributed. New versions are called
"NewOS.boot" (or "NewOsV.boot", the variant that supports the file version numbering facility).
You should transfer NewOS.boot to your disk and install it by saying "Install NewOs.Boot". It
will ask you several questions which determine it’s configuration on your disk ("SysGen", if you
will parden the expression) and finally the Executive will be invoked. The newly configured OS
writes itself on the file Sys.boot, so you can delete NewOS.boot after installing.
- When you wish to ERASE a disk completely and re-initialize it. This option pauses to let you
insert the disk pack you want initialized. This "new disk" function is invoked by answering
affirmatively the question "Do you want to ERASE a disk before installing?" after answering
affirmatively that you want the "Long installation dialogue". See also the NEWDISK section of
the Alto Subsystems Manual.
- When you wish to change the "user name" or "disk name" parameters of the operating system.
The install procedure will prompt for these strings. It is also possible to specify a disk password
that will be checked whenever the operating system is booted.
- When you wish to enable the "multiple version" feature of the file system. (Because few programs
presently cope with all the subtleties of this feature, it is wise to leave it disabled.)
- When you wish to extend a file system. Basic disks are often kept on Interim File Systems from
which users can copy them with CopyDisk. They are usually configured for a single Diablo
model 31 disk. If your machine has more disk space, you can extend the file system by answering
"Yes" to the question "Do you want to extend this file system?" (this is also part of the "long
installation dialog").
6.2. How to get out of trouble
It occasionally happens that a disk will not boot, or something runs awry during the booting process. In
this case, the following steps should be considered:
1. Run the Scavenger. This can be done in two ways:
Place a good disk in the Alto, and invoke the Scavenger. When it asks if you wish to change
disks, respond affirmatively, put the damaged disk in the machine and proceed when the
drive becomes ready.
If you have network access to a "boot server", hold down the <BS> and <’> keys and push the
boot button. Continue to hold down <’> until a tiny square appears in the middle of the
screen. You should now be talking to the
Network Executive; type Scavenger<cr>.
Alto Operating System May 5, 1980 27
For Xerox Internal Use Only -- December 15, 1980