[vcf-midatlantic] Random numbers
David Riley
fraveydank at gmail.com
Sun Apr 9 06:54:50 EDT 2017
On Apr 8, 2017, at 13:06, Dave McGuire via vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>
> On 04/08/2017 12:10 PM, Dan Roganti via vcf-midatlantic wrote:
>>> Remember,
>>> that step to seed the rnd generator is not perfect either
>>>
>>> , eg. RND(-32768) or whichever value
>>> if you use the same seed, guess what,
>>> you get the same random numbers :)
>>
>> This is why you like to use something "random" to seed the rnd generator
>> Usually every computer has a free running counter,
>> meaning it's constantly being updated in the background
>
> If some of my dustiest neurons are working, in the Atari at least there's a scan line counter from the video subsystem available for reading. At least I think it was something like that. That was great for seeding random number generators. The Apple ][ must have something like that.
Hahaha, NOPE. The Apple II is EXTREMELY Spartan hardware. There's not even a timer in there. The only hardware you can count on is RAM, some ROM, the (0 or 1 valued) cassette interface, and some miscellaneous stuff (speaker output, paddle connector, etc.).
Getting good entropy to seed is hard on an Apple II.
- Dave
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