6 Aug
2015
6 Aug
'15
11:43 a.m.
Acch. All this modern/complicated stuff. Once you powered on an IBM
1410 (2 seconds), you could have it (141O O/S: 1410-PR-155) running in
as little as a minute, counting the tape drive mount:
Mount tape on unit 0 [30 seconds tops, as tape is probably already there]
Storage Scan to +1
Sense switches to a blank character
[The above two were normally left that way]
Mode switch to CE
Computer Reset
Start
00000 [This clears storage]
Computer Reset
Move Mode Switch to Display
Start
00000 [Display before altering]
Press margin release on console typewriter while it types out "bbbbb"
Computer Reset
Move Mode Switch to Alter
00000
A(WM)L%B000012$(WM)N [Read tape to end of core/record to loc 12]
Computer Reset
Start
[Wait about 10 seconds for 1410-PR-155 to load]
:)
On 8/6/2015 1:21 PM, Fred Cisin wrote:
> Wow.
I'll never complain again that it takes too long to boot Windows...
On Thu, 6 Aug 2015, geneb wrote:
One thing I don't understand - why can't
the machine boot on its own?
Why would IBM design a computer that required another computer just to
boot it?
"Why CAN'T the operating system have full functionality during booting?"
I had an interesting conversation almost 30 years ago with a published
expert on operating systemes and C programming, when he was bothered by
why IO.SYS/IBMBIO.COM and DOS.SYS/IBMDOS.COM had to be in specific
places on the drive.
"Booting" is of course short for "bootstrapping", which is a
multi-hundred year old term for a obviously ridiculously impossible
task: "pulling yourself up by your bootstraps".
I had always thought that that derived from Baron Von Munchausen,
but a little research turns up that the baron had lifted himself
and his horse out of the swamp by his pigtail, not his bootstraps.
It wasn't until early 1800s that "bootstrapping" became the iconic
example.
The reason that IPL is called "booting" is because it is such an
obviously ridiculously impossible task.
"You can't use the operating system to load the operating system."
Obviously it is simplest if somebody (or machine) outside, loads
the code into memory, and then triggers a GOTO.
Which is cheaper, or more reliable, a "trained" operator, or a
smaller external machine?
The really clever way, though, was to toggle in, or have a little ROM,
to load a TINY bit of stored code ("boot sector") into RAM, GOTO it,
and it could contain enough code to load a bigger chunk, which could
have plenty of code to load the rest.
Why not just put the OS in ROM?
That would require more ROM, would make bug-fixes more difficult,
and would make it more difficult to modify the OS to add new
features, such as security holes.