7-Men and fast Hard drives

Endgame analysis using tablebases, EGTB generation, exchange, sharing, discussions, etc..

7-Men and fast Hard drives

Postby jshriver » Tue Feb 23, 2010 4:35 am

A while back I was reading about an egtb generator that mentioned the possibility of 7-men, but do to the intense memory usage it would require swapping to to disk. (Muller perhaps?).

Came across this today and thought maybe this would help with such a bottleneck.
http://www.physorg.com/news185438129.html#top

Essentially 2gig/s speeds on SSD.
Thoughts and comments are appreciated :)

-Josh
User avatar
jshriver
 
Posts: 287
Joined: Tue Jan 31, 2006 5:59 am
Location: Toledo, OH, USA

Re: 7-Men and fast Hard drives

Postby koistinen » Tue Mar 23, 2010 9:51 am

The problem with SSD drives is that the bytes on it are more expensive.
The advantage of mine and h.g.mullers algorithm is that they work well with normal hard disks because they don't need all that many seeks.
With mine, reading and writing disk in blocks of 16 MB is reasonable on a machine with 6-8 GB of ram.
As the results need to be stored anyway, you can use 6-8 disks in parallel and thus get speeds of perhaps 1 GB/s today without spending more than you have to.
(I am on the job and have hopes of getting the program written in 6 months.)
koistinen
 
Posts: 80
Joined: Fri May 02, 2008 7:59 pm
Location: Stockholm

Re: 7-Men and fast Hard drives

Postby guyhaw » Sun Apr 04, 2010 6:55 am

I haven't being paying much attention recently.

Have their been developments to EGT-algorithm algorithms that significantly reduce the number of I/O disc-transfers?

I conjecture that the best way to optimise is to notionally divide the index-range of positions into a number of subranges and 'park' requests for information about positions in those subranges until there is no alternative but to go and look up that subrange (which would be done in one disc transfer if the subrange was small enough or the disc transfer big enough).

The same idea works on a cluster-machine where a balance has to be struck between immediacy of request and congestion on the 'backplane' network.

g
guyhaw
 
Posts: 489
Joined: Sat Jan 21, 2006 10:43 am
Location: Reading, UK

Re: 7-Men and fast Hard drives

Postby koistinen » Mon Apr 05, 2010 9:58 am

koistinen
 
Posts: 80
Joined: Fri May 02, 2008 7:59 pm
Location: Stockholm


Return to Endgame Tablebases

Who is online

Users browsing this forum: No registered users and 1 guest