Thread View: comp.sys.dec.micro
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2 total messages
Started by George A. Theall
Sat, 20 Apr 1991 04:21
Rainbow EchoMail Digest
Author: George A. Theall
Date: Sat, 20 Apr 1991 04:21
Date: Sat, 20 Apr 1991 04:21
127 lines
4400 bytes
4400 bytes
Rainbow EchoMail Digest Apr 19, 1991
In this issue:
RE: FLOPPY INFO
RE: MS-DOS 3.10 OR LATER
RE: FREE STUFF ACT FAST (2 messages)
WARNER WANTS TO KNOW
Articles posted to either INFO-DEC-MICRO or comp.sys.dec.micro are
currently gatewayed to the Rainbow Echo on FidoNet. You do not need
to take special action to respond to articles in these digests.
Please send reports of problems or suggestions for improvement of
this digest to GTHEALL@PENNDRLS.UPENN.EDU (Internet).
------------------------------------------------------------------------
Date: 14 Apr 91 20:00 -0500
From: FRANK MALLORY
To: GEORGE THEALL
Subject: RE: FLOPPY INFO
GT> I have used the DEC pre-formatted RX50K and the Maxell MD1DD-RX50
GT> pre-formatted diskettes on the DECmate II extensively. The Maxell
GT> disks are *clearly* superior to DEC's offering. This is seemingly
GT> contrary to other's reports, but there is a proper explanation:
The Maxell diskettes I have trouble with are the MD2-D, which is their
regular DSDD diskette designed for use on 360KB PC drives.
- --- msged 1.99L MSC
* Origin: Silver Bullet - Silver Spring, Md. - 301-622-2247 (1:109/417)
------------------------------
Date: 15 Apr 91 12:46 -0500
From: ALAN RASKIND
To: AMER NELSON
Subject: RE: MS-DOS 3.10 OR LATER
Thank you for the info. If anyone knows where locally (in the Los
Angeles area) I can get a bug free copy of DOS 3.10b for the
Rainbow please let me know. Also any info on what version of
Code Blue needs to be use with it? Thanks, Alan
- --- QM v1.00
* Origin: Beach Cities RB (1:102/139.0)
------------------------------
Date: 15 Apr 91 14:17 -0500
From: BILL ROGERS
To: GEORGE THEALL
Subject: RE: FREE STUFF ACT FAST
I'll take anything left over. Just mail it COD to;
Bill Rogers
8412 Steilacoom Blvd #15
Tacoma WA 98498
I especially need a copy of the DOS!
Thanx
Bill
- --- Opus-CBCS 1.12
* Origin: Glacier Peak Rainbow, Bellevue, WA - 206/644-8431 (1:343/3.0)
------------------------------
Date: 15 Apr 91 14:21 -0500
From: BILL ROGERS
To: GEORGE THEALL
Subject: RE: FREE STUFF ACT FAST
If you have already gotten rid of most of the stuff, then I need the
DOS & CP/M disks most. I could also use a keyboard.
Thanx again.
- --- Opus-CBCS 1.12
* Origin: Glacier Peak Rainbow, Bellevue, WA - 206/644-8431 (1:343/3.0)
------------------------------
Date: 18 Apr 91 21:08 -0500
From: FRANK MALLORY
To: GEORGE THEALL
Subject: WARNER WANTS TO KNOW
GT> From: ccjason@ucdavis.ucdavis.edu (Jason Gabler) Organization:
GT> University of California, Davis
GT>
GT> In article <1991Apr16.162010.24517#Solbourne.COM> imp@Solbourne.COM
GT> (Warner Losh) writes:
GT> >
GT> >P.S. Does anybody know what it means when you turn on your Rainbow
GT> >and NOTHING happens? No screen, no fan, no disks spin up? No, it
GT> >isn't upplugged... :-)
GT> >--
GT> >Warner Loshimp@Solbourne.COM
GT>
GT> it means: 1) Some one at DEC forgot about UL standards 2) You don't
GT> have an IBM PC
I had this happen on an IBM PC once, and it almost drove me crazy until
I discovered that an aluminized write protect tab had fallen
off a floppy and was shorting out the drive electronics. I
don't use aluminized write protect tabs any more (if any).
On the Rainbow, tho, I think it is more likely to be the on/off switch.
It's pretty easy to substitute a new fan assembly with on/off
switch to check it out.
- --- msged 1.99L MSC
* Origin: Silver Bullet - Silver Spring, Md. - 301-622-2247 (1:109/417)
------------------------------
End of Rainbow EchoMail Digest
******************************
Re: Rainbow EchoMail Digest
Author: Charles Lasner
Date: Sun, 21 Apr 1991 19:15
Date: Sun, 21 Apr 1991 19:15
49 lines
3731 bytes
3731 bytes
I was the one quoted here again, so I'll reply about the Maxell diskettes. Anytime you use hub-ringed diskettes in a 96 tpi drive, you are taking a high-risk chance with your data. The condition of the drive (dirt, age) as well as the condition of the diskette, as well as its manufacture, dictate your (slim) chances of long-term reliability of the data. The problem is that those diskettes were designed to deal with the problems of the widespread DD-type drives used on a million poor xt clones. Many of these crappy drives chew up the hub areas of the diskettes. Any of you out there remember what RX01s do to the 8" diskettes? Any of you remember the third-party add-on user-installable hub-rings? The 48 TPI 40 track drives used with those DD disks have "non-thin-film" heads, to coin a retroactive phrase. This means that each track, which owns 1/48 " uses about 50% of this space for data recording. The rest is guard zone and tunnel erase zone. This is also why you can read the DD disks in the HD drives so easily; basically you can't miss :-) The 96 TPI disks, like the RX50, use thin-film heads. Not as snazzy as the HD disk drives like TEAC FD-55GFR, as used in good AT-clones, but 96 TPI none the less. This of course means that each track owns 1/2 of what the corresponding track owns in the 48 TPI drive, but it doesn't end there. The thin-film heads use a shorter magnetic gap, which translates into far less use of the media than would otherwise be predicted, about 1/5 as much. So, this means that 96 TPI drives record their data on about 1/10 of the media as do 48 TPI drives. The chances that the media's hub-rings can be grabbed differently each time now greatly increases chances of data errors. Each time the diskette is passed through a hub-chewing drive, the greater the likelihood that a 96 TPI drive can't reliably use that diskette. Further, some vendors, possibly Maxell, will use somewhat thicker hubrings, in an attempt to produce better results with the intended use on DD drives, which only worsens prospects for use on 96 TPI drives. I myself have had problems using 3M diskettes intended for DD usage. The DSDD media were formatted on HD 96 TPI drives in DD format for possible reading on DD drives (360K). They were unreliable on other HD drives due to the slight wear on the hub-rings. Registration errors were high because the HD drive couldn't reliably grab the media in the same place. We resorted to pulling the media out and reseating it a lot to retrieve the data with many retries. If the same media were reformatted on the target drive, and not removed and reseated, it read back fine. Removing and reseating the diskette made it flakey even on the drive that formatted and wrote it moments ago. These same diskettes worked fine on TEAC FD55B drives (DD 360K), because the hub-rings are not really that worn, just beyond the tolerance limit for 96 TPI mis-use. cjl (Charles Lasner) (lasner@watsun.cc.columbia.edu)
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