Hi, when checking USB stick benchmarks, I came across some interesting facts...
- sticks with MLC store up to 3 bits in 1 cell, which costs less but is slower (compared to SLC) - Vista readyboost uses USB sticks as swap space, which is useful in particular when things get swapped out (in other words: you have not enough RAM). Sticks have slow transfer but no seek delay. - unfortunately the delay for write access is much longer than for read access in USB sticks... - As http://preview.tinyurl.com/5tsx4o shows, in particular writes get a lot faster if you write in blocks of 32 kBy or more The image linked via tinyurl is from a thread about an OCZ stick with dual channel controller and MLC chips. It seems that SSD and high speed USB sticks with SLC chips generally have way shorter write delays but dual channel MLC is still nice if you use larger files such as audio and images :-). www.ocztechnologyforum.com/forum/showthread.php?t=34372 So... What does that tell us for DOS usage? Well it explains why my DOS was so ridiculously slow when I used Windows 3 from a MLC stick a few years ago... Two possible reasons: 1. the BIOS USB storage driver only used slow USB 1.1 and not USB 2.0 and 2. because DOS has no idea what USB stick means, it will often do single sector writes, for example to update the FAT or a directory entry. Could mean 20-100 msec of delay for each write access...! You can try to load "lbacache flop" and "tickle /lba" to "inflate" small (below 2 kB) reads to chunks of 4 kB if they start at a multiple of 4 kB. All of those setup parameters can be changed by recompiling but maximum chunk size is 8 kB (must fit in the 9 kB floppy buffer). You can also try "tickle /chs". Let me know if the lbacache flop tickle lba combination makes your READS faster and if I can send you tickle versions with other settings for comparison, thanks :-). Of course what you really want is a cache with pooled WRITES to make sure that larger blocks are written and less write delay happens. As far as I can tell, UIDE does not support that yet, but DR DOS NWCACHE does :-). Note that NWCACHE calls pooled buffered and supports it only for DOS-removable drives like diskettes, using the lookahead buffer? You can still use the NWCACHE delayed write feature on all disks, though. Try the options: 16 kB low RAM lookahead 1/3 sec 64 kB delayed: nwcache 6144 6144 /lend=off /bl=16 /delay=333 /w=64 /flush=off Thanks for trying :-) Eric PS: I do not know whether NWCACHE caches LBA. If it has no effect on your stick, try using SYS CONFIG to force the kernel to use CHS. Be WARNED that you can only use the first 8 GB of all disks / sticks after disabling LBA in your kernel with SYS CONFIG though! ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
