My Apologies

[Rodrigo]

Originally Posted by axn

Not really, but that was not what I was referring to. I was talking about the attempts to install linux.

Oh, I see, thanks.

Yeah, I'm inclined to leave it alone in terms of the operating system. But I'd still like to find some out-of-the way spot where the old machine could settle in and contribute (if ever so modestly) to the project. Trial Factoring in the LMH zone has been suggested, and now that we've learned that OBD appears to require changing the OS the choice is getting clearer. I'll be looking into LMH in the next day or two -- hopefully I can find a place there to park my box where it can chisel away without bothering anybody.

Rodrigo

[Uncwilly]

Originally Posted by Rodrigo

Yeah, I'm inclined to leave it alone in terms of the operating system.

I might be able to dig up the version of Linux that I tried, it allows all of the Linux files to reside on a DOS partition. You boot to DOS. Then you go to the Linux directory and launch it. It loads itself. All of the Linux files are contained in the Linux directory. It also loads support for the FAT file system. It is on an old laptop that I haven't fired up in 3-5 years. (I may have copied all of the files to an external HDD.

[ET_]

Originally Posted by Rodrigo

Luigi,

Thanks for getting back to me on this. If not Pentiums, then which processors are your programs optimized for -- later (or earlier) Intel CPUs, or a different brand altogether?

And, is there any other software out there, from anybody else, that would enable this PC to do OBD?

My P75 has 128MB of RAM in it, FWIW.

Rodrigo

IIRC, there was a program called simply Factor that could run in DOS. Other primality proving and factorization programs are maintained by Will Edgington here. Some of them should run under a DOS extender.

Pentium 4 should run Factor5 and Factor4. Maybe there was a version of Factor4 that run on Pentium III. Our friend WBLIPP (coordinator of OBD) used an old version of Factor (I guess 3.2) on his PPro 233, but I don't recall which OS he had.

Sadly enough, pfgw is based on Woltman's GWNUM library, and can't handle factorization of huge Mersenne numbers (its form evaluator crashes).

Luigi

[Rodrigo]

Luigi,

Thanks for looking, I appreciate it.

If Uncwilly can find the Linux version that works off a DOS partition, then the P-75 may be back as a possibility for OBD. Otherwise, I'll dedicate the P-233 and/or the PII-400 to OBD, using Factor_x for Windows. Which version do you recommend for these CPUs?

Rodrigo

[Rodrigo]

Uncwilly,

So with this version I would simply boot to DOS as normal, and then instead of continuing on to Windows I would load Linux as if it were a DOS application? That would be very cool.

Before we get into further complications such as dealing with a new OS, though, maybe it's better to exhaust simpler possible alternatives. Is there a range where I could park that P-75 to quietly do Trial Factoring for a while and it wouldn't quickly get in anybody's way?

I'm looking (for example) in the 630M ( http://www.mersenne.info/?s=630000000&d=2&t=1 ) and 857M ( http://www.mersenne.info/?s=850000000&d=2&t=1 ) ranges. Is a page like this one: http://www.mersenne.org/report_facto...=1&B1=Get+Data sufficient to decide whether I can/should ask to be assigned numbers there?

Rodrigo

[Primeinator]

I think all of those exponents have been factored past 62 bits (which, if I remember correctly, was the limit of what your oldest machine is capable of).

[lavalamp]

Originally Posted by chalsall

Yeah. Hundreds of years...

Or 24.

Originally Posted by http://primes.utm.edu/top20/trends.php

The slope 0.079 (over past 60 years) corresponds to doubling the digits every 3.8 years, or 46 months.

Horribly out of context, but you can read the rest if you like.

2^d * 12,978,189 = 10^9

Where d is the number of doublings:

2^d = 77.05

d = log_2(77.05)

d = 6.268

Since each doubling takes 46 months, the time to reach 1 billion digit primes is:

T = 6.268 * 46
T = 288 months
T = 24 years

Obviously only a rough estimate, but it's not that long off, lets just call it about 25.

Edit: Oh, and the first 100 million digit prime in 11 to 12 years or so.

[EdH]

If your machines can boot from CD, you might take a look at Damn Small Linux (DSL) for a small linux OS that doesn't change anything of the resident OS. You can simply use the HD for storage.

However, heavy CPU usage does take a toll on older machines. Using them 24/7 would not preserve them for future availability.

A last thought: I recently dug a 386/16 out of storage to use for a simple door security setup and discovered that while it was sitting, the CR123 backup battery (soldered to the MB) leaked and destroyed all the surrounding traces, including the internal layers.

I, too, have some older machines around - I wonder what I could get a dozen TI-99/4A consoles to accomplish. . .

Take Care,
Ed

[chalsall]

Originally Posted by Rodrigo

I'm looking (for example) in the 630M ( http://www.mersenne.info/?s=630000000&d=2&t=1 ) and 857M ( http://www.mersenne.info/?s=850000000&d=2&t=1 ) ranges. Is a page like this one: http://www.mersenne.org/report_facto...=1&B1=Get+Data sufficient to decide whether I can/should ask to be assigned numbers there?

I would suggest you stay away from anything above 200M, as everything still at 63 bits has been officially reserved on the server and/or unofficially on the LMH Forum.

Besides, everything between 310M and 350M will be completed in approximately 48 hours....

[Rodrigo]

Originally Posted by chalsall

I would suggest you stay away from anything above 200M, as everything still at 63 bits has been officially reserved on the server and/or unofficially on the LMH Forum.

Besides, everything between 310M and 350M will be completed in approximately 48 hours....

chalsall,

Thanks for the scoop.

How about 190M? http://www.mersenne.info/?s=100000000&d=1&t=1

Which leads me to something I'd been meaning to ask. After all these years and with so many people participating, why is there (apparently) still so much work left undone in the very low ranges? (I.e., http://www.mersenne.info/?s=0&d=2&t=1 )

No doubt there is a good reason.

Rodrigo

[Rodrigo]

Ed,

Thank you for the warning re: the backup battery. Bummer. If I understand the issue correctly, this is a problem mainly when the computer has been left unplugged (or is it, simply unused) for long periods of time. Sort of like the batteries in a child's toy, if nobody turns it on for a few months they can leak.

Unfortunately, the P75 came out when CD-ROMs were just getting started, and just like I can't write to it (only read from it), there's no provision in the BIOS for booting from it.

On the TI99/4A's, I can relate. It was a neat time when a whole new world was opening up before us. In addition to my Sanyo MBC-555, I have an Amstrad PC6400DD that gets fired up once in a while to play '80s vintage games. Sadly, it just doesn't have the memory or storage capacity to run any version of Prime95 (AFAIK, which may not be very far).

Rodrigo