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BOOTSTRAP LOADER PROGRAM LOGIC
The Bootstrap Loader is a system that allows the user to read
the Paper Tape Loader into the region of RAM that begins on
a 256-word boundary using a specially formatted tape.
1.
Bootstrap Tape Format:
The Bootstrap Tape consists of two sections.
section consists of a direct core image of the second level
bootstrap (described be l o w) , preceded by a block of rub-
outs.
In this section of the tape, each frame corresponds
directly to one data byte.
the Paper Tape Loader in standard object format.
2.
Overall Logic:
The Bootstrap Sequence Procedure, is as follows:
a.
The user keys in a simple 32-byte bootstrap, starts it
up, then starts the tape reader on the teletype.
b.
The basic bootstrap reads in the second level bootstrap
from the first part of the bootstrap tape and starts
it up.
c.
The second level bootstrap stops the tape reader then
checksums itself to make sure it was loaded correctly.
If not, it hangs up.
d.
If the second level bootstrap checksums correctly, it
starts the tape reader and reads in the paper tape
loader from the second part of the bootstrap tape and
locates it in the 256-byte page specified by the PRO
GRAMMED INPUT switches.
the tape, it stops the reader and hangs up.
e.
When the Paper Tape Loader is completely loaded, it
stops the paper tape reader, then starts up the Paper
Tape Loader.
3.
Basic Bootstrap:
The Basic Key-In Bootstrap was designed to be as short as
possible.
It merely reads in characters.from the tape and
stores them directly into memory.
byte of FF hex, it resets its pointer and counter.
allows it to use the block of rubouts at the beginning- of
the tape to synchronize on.
IMSAI 8030
B o o t s t r a p
P r o g r a m L o g i c
The second section consists of
If it detects an error in
Whenever it reads in a
L o a d e r
The first
This
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