Path: news!news-feed.netvision.net.il!Pollux.Teleglobe.net!proxad.net!freenix!sunqbc.risq.qc.ca!newsfeed.mathworks.com!newspush.london1.eu.level3.net!level3eu!newspeer.highwayone.net!colt.net!news0.de.colt.net!news-fra1.dfn.de!news.Uni-Mainz.DE!not-for-mail From: Andreas Magenheimer Newsgroups: comp.sys.atari.8bit Subject: Re: 3.5 Drives and Disks Date: Thu, 30 Mar 2000 14:38:57 +0200 Organization: Johannes Gutenberg-Universitaet Mainz, Germany Lines: 56 Message-ID: <38E34AE1.8A0667FC@mail.uni-mainz.de> References: NNTP-Posting-Host: ispp9.sowi.uni-mainz.de Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: bambi.zdv.Uni-Mainz.DE 954419736 28568 134.93.160.192 (30 Mar 2000 12:35:36 GMT) X-Complaints-To: usenet@mail.uni-mainz.de NNTP-Posting-Date: 30 Mar 2000 12:35:36 GMT X-Mailer: Mozilla 4.5 [de] (WinNT; I) X-Accept-Language: de,en Xref: news comp.sys.atari.8bit:58898 Atari Bob schrieb: > > I had noticed some traffic about 3.5" drives and disks a while back - what > works with what and how to use this and that. So, I did some tinkering which > I will share with the group. > > This was done on an XF551 with suitable code changes to accomodate the 3.5" > format (80 tracks, spin up, seek timing....). These changes are available > all over the place, I think. If not, I have them as a text file. > > The basic question was: Can you use a modern 1.44MB drive and diskette on > the XF551? > > Yes, you can - at 720K only. The drive will sense the 1.44 diskette and > alter the frequency response of the electronics for 1.44 operation if you > use a 1.44 disk in a 1.44 drive. In a 720K drive OR using a 720K disk (no > hole in the upper left corner), you are OK. It is getting really hard to > find 720K disks and drives, though, so what to do? > > What I did was to kill the density sensor in my drives. Now, ANY disk I put > in there is going to run at 720K, regardless of a hole or not. To do this > you need to carefully inspect the drive. I used TEAC FD-235HF drives. There > are many, many variations of these drives, but the new ones all seem to be > similar. Looking at the bottom of the drive (where all the wiring is), with > the front of the drive pointing UP, there is a small switch in the upper > right hand corner. All of the TEAC drives seem to use a mechanical switch > that is normally open to sense the density. Just by shorting out the > contacts on this switch, you set the drive into permanent 720K mode. Mine > worked just fine - I just solder-bridged the contacts and plugged it in. > These drives sell new for less than $20, but be careful - some of the models > do not have any way to change the address to D0 for use on a stock XF551. > You can just re-wire the flat cable like they do in the PC if this is a > problem. > > As for the diskettes... I used both 720K and 1.44 diskettes in all > densities with NO problems at all. DD, ED and SD all work fine. I do believe > that the recording medium on the 720K and 1.44M disks is the same, unlike a > 720K and 1.2M 5 1/4 disks. The 5 1/4 started life as SD and evolved into a > 1.2M at four times the bit packing. The 3.5 has really only been doubled > from 720K.... > > No more haunting the bone yards for 720K stuff!! > > Bob Hello Bob, why should I kill the HD sensor on HD drives ?? Just use a write protection tab (or something similar) from the old 5,25" disks and put it over the HD hole: Now the HD drive detects it as a DD disk and formats it with 720k. I know, these tabs are not so fine, they get loose after some time, but they are easier and cheaper to handle than killing the HD sensor in a 3,5" drive. Besides, there is a way to upgrade the XF drives to full HD (1,44MB/16Mhz) capacity and even to ED (2,88MB/32Mhz) capacity if you like. So, better don`t kill the HD sensor yet, you may need it in the future... Andreas Magenheimer