Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpl-opus!hpccc!samc From: samc@hpccc.HP.COM (Samuel Chau) Newsgroups: comp.sys.ibm.pc Subject: Re: Perstore and Maxtor Message-ID: <5060053@hpccc.HP.COM> Date: 15 Feb 89 21:59:14 GMT References: <16761@srcsip.UUCP> Organization: HP Corporate Computing Center Lines: 59 > Has anybody had any experience with perstore controllers and Maxtor drives?? > I have a Maxtor xt-1140 120 Meg drive (MFM) and from what I hear I could > get as much as 200 Meg out of it. I haven't actually tried formatting an XT-1140 with the Perstor PS180, but I'm quite certain that if the drive was manufactured recently (less than 2 years old or so) then you should have no trouble getting 200 Megs out of it. > What is the interleave of a perstore controller (1:1, I guess)? The best that the PS180 can do is 3:1 interleave, which translates to a maximum transfer rate of about 310 Kbytes/sec. Having a fast CPU or fast AT bus clock won't be of much help, since the overhead is in the controller itself. In fact, the optimum interleave should be the same for a 6 MHz AT as for a 20/25 MHz 386 PC. I believe Perstor is working on an improved version of the controller that can support a 1:1 interleave. (Don't know the targeted release date, sorry) > All Maxtor drives use plated media; I understand plated media is a requirement > for RLL drives. (please tell me if I am mistaken) The first statement is correct. Maxtor doesn't use oxides. But I don't think plated media is a must for RLL drives. It will certainly help, since plated media is of higher resolution than oxide media. What is required of RLL drives is high rotational accuracy and sufficient media resolution. Flux density on the surface is NOT higher for RLL compared to MFM encoding, but the timing requirements (i.e. accurate placement of the flux reversals on the surface) are much more critical for RLL. Perstor controllers have similar requirements as RLL. Rotational accuracy of the drive spindle motor must be kept within 1%. Plated media drives generally have a better chance of working with the PS180 than oxide drives. Cables must be of good quality, kept as short as possible, and of course, properly terminated. Given all this, the chance of a Maxtor XT-1140 working as a 200 Meg drive should be excellent. Perstor also has a list of drives that are supported by the PS180. Virtually all Maxtor ST-506 models utilizing MFM encoding are on the list. In case you don't know, there are two Perstor controllers currently in the market. The PS180-16F is a floppy/HD combination controller with a 16-bit bus interface. The PS180 is a HD-only controller with an 8-bit interface. I was told that the PS200 series controllers would soon be released from Perstor. These controllers will format the drives to 34 sectors/track, thus giving you 2X the capacity of MFM-encoding. RLL-certified drives are required, though. > 'Seek out new life and civilizations' | Brynn Rogers Honeywell S&RC > "Honey, come see what I | UUCP: rogers@orion.uucp > found in the refrigerator!" | !: {umn-cs,ems,bthpyb}!srcsip!rogers > | Internet: rogers@src.honeywell.com Sam Chau HP Cupertino samc@hpda (408) 447-0238 '...To boldly go where no Winchester has gone before..."