paul_gauthier@brains.UUCP (Paul Gauthier) (08/05/89)
ARLL HD controllers; are they any good?:
I recently heard of a beast called an ARLL (Advanced RLL) controller which
purports to, through some twist or enhancement of the RLL storage scheme,
increase your HD capacity by between 2 and 3 times. (So a 40M might come out
at 2.5 x 40M = 100M). The company (who's name I forget) changed the name from
ARLL due to the bad connotations that have come to be associated with RLL. I
don't know the new name.
Are these beasts all they claim to be? How do they achieve this storage
increase? Algorithmic data compression (I hope not, since 90% of my files are
compressed with ARC/ZIP/and_friends so additional compression won't really
help)? What are the price ranges for these controllers and what types of HD
will they work with? Must I get an RLL-rated HD or is it safe to try my luck?
Who should I contact to find one?
I'm running an XT-clone which currently has a 20meg Seagate drive and an
MFM controller. I'm considering purchasing an additional 80Meg drive and if
an ARLL controller would double or triple that I'd be very interested in
getting one.
--
-===------===- From Paul Gauthier at Cerebral Cortex BBS System
-==-==----==-==- (902)462-7245 3/12/2400 8N1 24h/7d
-==-------==------ paul_gauthier%brains@iisat.UUCP
-==-==----==-==- {uunet, utai, watmath}!dalcs!iisat!brains!paul_gauthier
-===------===-davidsen@sungod.crd.ge.com (ody) (08/09/89)
ARRL gives 31 sectors, or about 90% increase. I believe the only one
shipping anything like this is Perstor, and theirs is a slightly
diferent scheme, although they also give 31 sevtors. I had one of the HD
only versions and it worked fine, but was DOS-only. The new version is
AT controller compatible and should run OS/2 or UNIX as well.
bill davidsen (davidsen@crdos1.crd.GE.COM)
{uunet | philabs}!crdgw1!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -mewek@point.UUCP (Bill Kuykendall) (08/11/89)
>ARLL HD controllers; are they any good?:
We have 2 Perstor controllers running in separate systems with Seagate ST-
4096 drives. The 4096s format to about 76 meg MFM, 140 meg ARLL.
Both of the techs that are testing the controllers have reported minor
problems that bother me more than a little bit. Both systems periodically
"grind" while writing files. The Perstor does a read-after-write-verify on
data it has written, and the grinding noise is caused by rewriting the same
sector several times while attempting to correct an error. At first, these
episodes were always successful at writing the sector. After several
months though, both techs have reported failures during writes.
If you're considering one of these controllers, there's one other piece of
information you need. They don't work on all drives. The company we
purchased the controllers from were also selling 'Perstor Certified' 4096s.
We purchased the first controller without a drive and tried 4 4096s before
we got one to format. We then bought the certified drives to do our testing
with. As far as I'm concerned, they failed the test.
I am also testing a WD 1006 SVR2 controller (with 2 4096s). The drives
format to about 115 MB, and have worked beautifully so far (about 3 1/2
months now).aris@tabbs.UUCP (Aris Stathakis) (08/12/89)
From article <[1431.2]comp.ibmpc;1@point.UUCP>, by wek@point.UUCP (Bill Kuykendall): !>ARLL HD controllers; are they any good?: ! ! I am also testing a WD 1006 SVR2 controller (with 2 4096s). The drives ! format to about 115 MB, and have worked beautifully so far (about 3 1/2 ! months now). I've had a Maxtor 1085 (71MB) hard drive running on a Data Technology DTC 7287 RLL controller which gives me about 105 MB. It's been running for about 3 months NONSTOP (it's a UUCP server) with no hassles. With its 1:1 interleave, Spinrite tells me i have a 798k transfer rate (though Spinrite tends to lie a bit :-) which is really impressive. aris -- Aris Stathakis ..!<smart-host>!ddsw1!olsa99!tabbs!aris - UNIX is like sex - if you've tried it, you can't get along without it. - - If you haven't you really have no idea what the fuss is all about! -
mrichey@orion.cf.uci.edu (Mike Richey) (08/12/89)
In article <[1431.2]comp.ibmpc;1@point.UUCP> wek@point.UUCP (Bill Kuykendall) writes: >>ARLL HD controllers; are they any good?: > >We have 2 Perstor controllers running in separate systems with Seagate ST- >4096 drives. The 4096s format to about 76 meg MFM, 140 meg ARLL. > >Both of the techs that are testing the controllers have reported minor >problems that bother me more than a little bit. Both systems periodically You are correct. The problem with low cost drives, such as the seagate and the miniscribe products is a device known as the pulse detector. This device detects the flux rotations from the disk surface as the surface passes under the r/w heads. Most seagate drives were designed with a pulse detector made by silicon systems. silicon systems still sells this product because that's what the drive manufacturers order. SI makes better ones, but they cost more. There are other controllers (not PC type) that simply will not work with the seagate and miniscribe products. So beware, if you want more out of the drive, be real sure about the drive....
davidsen@sungod.crd.ge.com (ody) (08/14/89)
In article <[1431.2]comp.ibmpc;1@point.UUCP> wek@point.UUCP (Bill Kuykendall) writes: | I am also testing a WD 1006 SVR2 controller (with 2 4096s). The drives | format to about 115 MB, and have worked beautifully so far (about 3 1/2 | months now). I took Karl Denninger's advice and got one of these to replace an Adaptek. No excitement, it just works. bill davidsen (davidsen@crdos1.crd.GE.COM) {uunet | philabs}!crdgw1!crdos1!davidsen "Stupidity, like virtue, is its own reward" -me