Booting an IBM MP 3000 S/390 System

[Jay Jaeger]

I should think that a set of manually entered bootstrap instructions
(i.e., not on a diode ROM board) would take considerably longer than 5s.  ;)

On 8/6/2015 1:43 PM, Johnny Billquist wrote:
> 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.
> 
>     Johnny
> 
> 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.
>>>
>>>
>>>
>>>
> 
>