doc/Booting.txt
Copyright (C) 2015-2017  Mikael Pettersson

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PDP10 Boot Sequence
===================

PDP6 / KA10 / KI10
------------------

See http://www.inwap.com/pdp10/rim10b.html and the 1970 PDP-10 Reference Manual.
The PDP6 appears to be similar except the the bootstrap loader has to be entered
manually rather than being read from paper tape.

* a 14-word bootstrap loader is entered into locations 1 to 016 via the data and address
  switches on the console and then started at location 1 (PDP6), or loaded and started
  via paper tape (KA10 / KI10 "readin mode")
* the bootstrap loader reads data blocks from the paper tape:
  - an IOWD, which contains a negated word count and a destination address minus one
  - a block of data words, as many as indicated by the initial word count
  - a checksum
  - a JRST instruction, which is executed to jump to the entry point in the block,
    or a new IOWD, which signals the start of another data block

So the data on the paper tape would be:

; the RIM10B bootstrap loader (not PDP6)
<word count, starting address>
<data 0>
...
<data 12>
<checksum>
<jrst 2>

; bootstrap program
; first block
<word count, starting address>
<data 0>
...
<data (word count)-1>
<checksum>
; second block
...
; initial instruction
<jrst entrypoint>

KL10
----

- console loads and runs KLINIT (KL INIT)
- KLINIT does:
  1. loads KL microcode
  2. configures the cache
  3. configures the memory
  4. loads KL bootstrap program from BOOT.EXB located on the boot device
- the KL bootstrap program loads and starts the monitor, e.g. PS:<SYSTEM>MONITR.EXE

KS10 / KD10
-----------

The 8080 console's code resides in PROM.  The console boots the KS10 by reading microcode and monitor
from disk (UBA 1, RH11 @ 0776700, unit 0) or tape (UBA 3, RH11 @ 0772440, unit 0), and then starting
the KS10 at address 01000.

Dolphin / KXF10
---------------

Not specified in available documentation, but the console hardware has similarities
with Jupiter/KC10's console, whose software is based on the KL10 console software,
so it is likely similar in operation.

Jupiter / KC10
--------------

- console is a PDP-11 compatible microprocessor (Fonz-11 chipset implementing the PDP-11/34 ISA)
- console software based on existing KL10 console software, with adjustments for changes in the
  KC10 processor and I/O devices compared to the KL10
- "hard-core" console stored in 12KB of ROM, loads 38KB "loadable" console from the boot device into RAM
- the loadable console loads a "run-time support program" (RSP) which provides additional functionality

XKL-1 / Toad-1
--------------

See Chapter 3.3, Processor Initializaition, and Appendix E, TDBoot Command Summary,
in the TOAD-1 System Architecture Reference Manual.

- microcode loaded from ROM on power-on
- POST
- 256KW Boot ROM at slot 0 section 10, contains TDBoot, DDT, diagnostics and tests
- TDBoot loads an .EXE file, into section 0 (pages 0 to 0777 inclusive), or
  pages 01000 up to the highest mentioned in the .EXE; TDBoot sets up a paged address
  space, EPT, UPT, SuperSection tables, page map tables, but no CST or SPT.  The Boot ROM
  is also mapped into section 36.  Trap handlers in EPT/UPT are initialized to refer
  into the mapped Boot ROM.
- The .EXE is usually loaded from a TOPS-20 to TOPS-10 structure (file system),
  default <SYSTEM>MONITR.EXE.0
- Alternatively the .EXE can be read from a raw SCSI disk or tape device (no file system involved)
  [presumably the .EXE is stored as-is in a sequence of blocks]
- Disks are low-level formatted with 128 word / 576 byte blocks, or 512 word / 2304 byte blocks
- TDBoot settings stored in NVRAM

Notes
-----

Booting an alternative monitor/kernel on KL10 and newer would seem to require producing an
.EXE file and storing it in a TOPS-10/TOPS-20 file system on the boot device, or possibly
at the physical start of the boot device.  The .EXE would be a container for the kernel,
or a loader which would locate and load the kernel.