#Cache Testing
11 messages in this thread
Reese,
Here's the first cut on my testing that we discussed last week. CD Speedway
does perform as advertised but less well than SpeedCache+, both of which
I've now tested, v1.01g for Speedway and v4.05 for SpeedCache+. Using an
8mb extended memory RAM drive for Speedway and an 8mb extended memory RAM
cache for Speedcache+, SpeedCache+ was noticeably smoother on playing
motion video once the movie clip had been loaded into the cache. In
addition, SpeedCache+ was loading the cache a bit faster than Speedway,
even though I was using the S:OFF parameter for Speedway. I attribute the
difference in playback smoothness to the fact that Speedway is doing file
I/O from the RAM drive whereas SpeedCache+ is operating directly from RAM
with no file I/O calls to the operating system.
My system is a 386-20, 16mb system RAM, 150 mb HD, ET-4000 video card,
running MS-DOS 5.0, Windows 3.1 and SuperStor 2.04. CD-Rom drive is a
Mitsumi CRMC-1000 which does meet the 150kb/sec MPC DTR spec. My setup is
fast enough so that it will play the Mammals movies fairly smoothly with no
cache at all; there are little occasional pauses but you have to look
closely to see them. SpeedCache+ will smooth those out very well. So will
Speedway, but the relatively long wait while it loads the next sequence
into the RAM drive is annoying. There are several such pauses during the
elephant movie, for example, but Speedcache+ will play the whole movie
through without any such pauses.
The rest of my testing was done in Windows, using an Aris MediaClips Jets
& Props CD disc set. The movie clips, which are MPC, and include sound, are
played through an Asymetrix Toolbook interface. Here again, playback from
cache was much smoother with Speedcache+, with only occasional pauses which
seem to be a shortcoming of ToolBook rather than anything to do with
caching. Speedway also improves over the no-cache situation, where DTR from
the CD causes lots of jerks, but even from Speedway's cache the pauses are
more frequent than with SpeedCache+, probably because of the extra overhead
of file I/O calls.
Tom
S1
Tom,
It would be interesting to see your config parameters.
Thanks.
Reese.
Reese,
My command line for CD Speedway is:
CDSPEED BP:H:\ C:8192 S:OFF
and it's the last line in my AUTOEXEC.BAT
Drive H: is an 8mb RAM drive. I've also experimented with an 8mb HD cache
(my HD is ESDI with 18ms access time) without any significant difference in
performmance, either from DOS or from Windows. Other factors I've played
around with are number of DOS buffers (2-30), number of buffers for the
CD-Rom driver (2-32), number of buffers for MSCDEX (0-128). For these last
two, allocating more than 4 buffers each doesn't improve performance by any
noticeable amount.
I pretty much agree with your position on read-ahead caching. When playing
motion video stuff from a CD-Rom drive at a 150kb/sec DTR, there's not
going to be a chance for the reader to get ahead of the display, unless the
movie is in some highly compressed format which can be decompressed very
rapidly after getting it into RAM. Some of the fractal compression and MPEG
demos I've seen show some promise of being able to do this.
Since I can get fairly smooth playback of Mammals clips (which are in
320×200 resolution) without even using a cache at all, I assume that the
DFF format of the clips is some sort of compression scheme, perhaps where
only the change from one frame to another is being recorded. The clips on
the Aris MediaClips discs use tiny 160×100 frames (they have a .CAV
extension, whatever that means) and are unwatchable with caching. Speedway
or Speedcache+ makes a big difference here, with Speedcache+ having the
edge. Any suggestions for improvement would be most welcome. I mailed the
registration card yesterday and look forward to upgrades for Speedway.
Regards,
Tom
Tom,
Try the following:
Build a config. file using the configuration editor as follows:
BP:H:\
C:8000
BUF:8
F:64
S:OFF
The only real change is the number of buffers for Speedway. Using 8
buffers will improve the time it takes for files to be copied to the cache.
Since you do have a great machine<g>, you should see a noticable
improvement here.
The only other recommendation I can make is to use a larger cache to the
hard disk. My configuration is the same as above with the C: parameter
changed to @ 12 Meg. (Only if you can afford the space). It could be that
your disks could use the room. Although Mammels is one that I have
personally tested.
The new version will most certainly aleviate the problems with read times,
in that both background reads and partial file reads are supported. Hope
to have it for you soon. Reese.
Reese,
Thanks for the reply. On this system, using CDSPEED bp:h:\ C:8192 s:off
will also result in 8 buffers and 68 files as defaults, which is the
configuration I've been using for the comparisons with Speedcache+.
Using Mammals as a test application may not be the best way to test
various caching combinations, since, on on my moderately fast system at
least, the Mammals movies run pretty smoothly with NO cache at all. Running
motion video clips from Windows is a far more demanding test, I think,
because of the multi-tasking that may be going on, and because of the
processing overhead imposed by the Windows GUI itself. The clips I've been
using are just miserable with no caching, quite a bit better with Speedway
and best (so far) with Speedcache+. Increasing the cache size here isn't
likely to help; the biggest of the aircraft movie clips is around 3.5
megabytes, so an 8mb cache is plenty.
With background reads and partial file reads, Speedway should be a real
contender, since it appears to have a good foundation on which to build.
Regards,
Tom
Thanks Tom…I think it's also important to note from your tests that you
are lucky enough to have 8+ megs. of RAM for caching. Most of us lowly
users with 4 Meg. or less need the hard disk caching option. As you found
in your tests, performance is pretty close to RAM caching.
Did you run any tests pertaining to a user who only has 4 Meg….the option
would be to set up Speedcache with let's say 1 Meg. giving 3 to Windows,
and setting up Speedway with an 8 Meg. hard disk cache with 1 Meg. for
Smartdrv or some other supplemental cache….might be interesting to see if
the product still works the same way…
The other question is whether drive type makes a difference here. We know
that MPC compatible drives will perform well even without caching in most
situations…however, what about the low end of the spectrum, i.e. non-MPC
drives like the DAC private label SONY unit and others. We have seen
excellent results using Speedway for these products.
Maybe other users could get involved here and let us know…
Reese.
P.S. Thanks for taking the time to run the tests! It is apreciated.
Reese,
With both Speedway and Speedcache+, the cache for motion video playback
needs to be at least as big as the largest clip to be played. Otherwise, no
effective caching occurs. In the case of Speedway, even those who don't
have much in the way of extra RAM can usually allocate enough hard disk
space for the cache to allow movie clips to be played from the cache. On my
particular system, the HD is fast enough so that there is no significant
performance difference with Speedway between using the RAM drive and using
the disk cache. The clip can still be pumped to the display fast enough so
that the display doesn't have to wait for the next block of data. This
might be a lot different on a 486/50 using local bus video, in which case,
using a RAM drive cache might be the best.
In contrast, Speedcache+ does all of its caching directly from RAM,
without the file I/O overhead of Speedway, which probably accounts for the
somewhat smoother performance. Also, with Speedcache+, during the CD
access, the data is being sent directly to the display while the cache is
being loaded, so there is no wait to see the clip, even though it may be
jerky at this point. Subsequent replays of the same clip are from the cache
with no CD access at all. This is what happens with Speedway also, except
that playing is from the cache only and we have to wait for the CD read to
finish before seeing the video. Apparently the upgrades you mentioned will
improve this and I look forward to testing them as well.
Regards,
Tom
Reese,
Correct the last paragraph of the long answer to read "unwatchable withOUT
caching"…Sort of got ahead of myself there <grin>.
Tom
Thanks again for your responses. Being that Speedway is NEW patent pending
technology in caching, we're exploring lot's of new ground for the new
release.
Reese.
Where do you get speedway – what is the cost – and does it do the same
thing for regular window and dos programs as say PCKwik and Smartdrive?
Jerry
Jerry,
Speedway is new technology. It differs dramatically from hard disk caches
in that it's patent pending technology is "file" caching. Because complete
files are loaded to the cache, rather than sector or track info (as in hard
disk caches i.e. Smartdrv) chances are good that even first accesses are
improved dramatically.
Where you get it is up to you….of course it is available just about
everywhere CD-ROM software or hardware is available. I've seen it featured
at Software Etc., Electronics Boutique, and others. TIGER Software sells
it direct, and you may also order it by placing your order via e-mail to
us. Retail price is $99.00, however, average street price is @ 79.00.
Reese.