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- Newsgroups: comp.sys.ibm.pc.hardware
- Path: sparky!uunet!charon.amdahl.com!pacbell.com!att-out!cbfsb!cbnewsg.cb.att.com!rnichols
- From: rnichols@cbnewsg.cb.att.com (robert.k.nichols)
- Subject: Re: Format 3.5 DD floppy as a HD, is it reliable?
- Message-ID: <1992Nov17.015550.5677@cbfsb.cb.att.com>
- Summary: The media are NOT the same
- Sender: news@cbfsb.cb.att.com
- Organization: AT&T
- References: <16883@umd5.umd.edu> <1992Nov11.043814.24722@datamark.co.nz> <dpatel59.721943441@uther>
- Date: Tue, 17 Nov 1992 01:55:50 GMT
- Lines: 23
-
- In article <dpatel59.721943441@uther> dpatel59@uther.calvin.edu (DINESH PATEL) writes:
- ...
- > Also, according to what I have
- >realised, HD and DD have the same material (Magnetic media)
- ...
-
- This is probably the most widely believed falsehood in the PC
- universe. As has been previously pointed out, all you have to do is
- open the shutter and look through the media at a light source. The
- magnetic coating on the HD disk is relatively transparent; that on the
- DD disk is opaque. The media are NOT the same. The HD medium is
- magnetically "harder," allowing the bits to be packed more densely
- without interference and requiring a higher write current.
-
- Use DD disks as HD at your own risk. The danger of data loss is
- aggravated by the characteristic that the data will appear to have been
- written OK and can be read back -- it's not until several weeks later
- that you find that the data on the inner cylinders has decayed away and
- can no longer be read.
-
- Bob Nichols
- AT&T Bell Laboratories
- rnichols@ihlpm.ih.att.com
-