Re: Re: Compressed Disks
Jay Maynard <[email protected]>
| Newsgroups | gmane.comp.emulators.hercules390.advocacy |
|---|---|
| Message-ID | <[email protected]> |
On Wed, Nov 06, 2002 at 04:06:10PM -0000, floyds_void wrote: > --- In [email protected], "somitcw" <somitcw@e...> wrote: > > For reading compressed data, unless you > > are short on CPU cycles, I believe that it > > is faster to do less I/O. Hercules is not > > an exception. Flex would not only not be > > an exception, but any MIPS limits imposed > > by a zOS license might leave extra Intel > > CPU cycles for other work? > When the ratio of processor speed vs disk speed is great enough, > as they are now on the average personal computer, then real > differences can be observed when using compressed disk images > vs normal disk images. If the ration drops by a magnitude or > two then then differences might not be so noticable. My email from Yahoo has been out the past day or so, so I've missed most of this disucssion...but I will point out one difference between Hercules and Flex that bears on this discussion: Hercules uses files in existing filesystems for DASD emulation, while Flex uses raw partitions. (I don't know if more than one emulated DASD device can be assigned to a single disk partition, nor how Flex handles dividing up the space in that case.) This allows them to avoid the overhead of dealing with a filesystem. I don't know how significant that is in performance comparisons, but it would tend to lessen the effect of I/Os in their overall performance equation. ------------------------ Yahoo! Groups Sponsor ---------------------~--> Get 128 Bit SSL Encryption! http://us.click.yahoo.com/JjlUgA/vN2EAA/kG8FAA/dpFolB/TM ---------------------------------------------------------------------~-> To unsubscribe from this group, send an email to: hercules-advocacy-unsubscribe-hHKSG33TihhbjbujkaE4pw@public.gmane.org Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/