Booting an IBM MP 3000 S/390 System

Johnny Billquist bqt at
Thu Aug 6 13:43:58 CDT 2015

PDP-8 with OS/8 on an RK05. From power up until booted and ready was 
basically the time for the disk to spin up, which was about 10 seconds.
The actual booting of the system is about 0.3 seconds. Add 5 seconds if 
you had to manually enter the bootstrap.


On 2015-08-06 20:43, Jay Jaeger wrote:
> 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.

Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

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