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From: masaru@media-lab.media.mit.edu.MEDIA.MIT.EDU (Masaru Sugai)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: A3090 tape driver ??(Re: BTN 2.0 Tape handler) (a bit long...)
Summary: How does tape drive store data in QIC cartrige ? (naive question)
Keywords: A3070, A3000, QIC, tape,
Message-ID: <5761@media-lab.media.mit.edu.MEDIA.MIT.EDU>
Date: 30 Apr 91 05:09:09 GMT
References: <1991Apr13.014520.13657@sugar.hackercorp.com> <61897@masscomp.westford.ccur.com> <5692@media-lab.media.mit.edu.MEDIA.MIT.EDU> <41542@cup.portal.com> <5704@media-lab.media.mit.edu.MEDIA.MIT.EDU>
Reply-To: masaru@media-lab.media.mit.edu (Masaru Sugai)
Organization: MIT Media Lab, Cambridge MA
Lines: 31

In article <5704@media-lab.media.mit.edu.MEDIA.MIT.EDU> masaru@media-lab.media.mit.edu (Masaru Sugai) writes:
>I'm still wondering how much I can actually store on a single cartrige.
>Any suggestions and comparisons (especially tape drives in other platform)
>are very welcome.

This is a silly question for hardware wizards, but I would like to know how my
QIC tape drive stores data on tape.

Today I bought a 3M DC6150, and tried full backup again but the result was 
similar. Tape was wound to near the end after dumping 27MB in 440 sec.  I
noticed there were changes in the motor sound, and I stopped tar 150 sec after
invocation to find out the tape was almost 'wound up'. I went through A3070
installation guide and made a simple calculation.

  DC6150 media volume    7,440 inches (620 ft)
  Data density	      	10,000 BPI		|  realistic backup time
                           9.3 MB 	        |      	2 min 30 sec
  Number of tracks	    18                  |
			 167.4 MB	        |     	45 min 

My calculation seems to be reasonable as 27MB backup amounts to one and half
r(w)ound trip.  This is my last concern on A3070 which has been holding me off
100% confidence over two weeks. Any info is appreciated.

PS
I placed my order on SCSI2/1 and custom 50F cable so as to hook it up to
NeXT and DECstation in our office. I might post my results...
-- 
-- Masaru Sugai:Use disclaimer. CIS 72050,2141:NeXT + A3000 = money-eater
NEC Corporation:sugai@ccs.mt.nec.co.jp DORMANT:hardwired logic,machine language
MIT R.Affiliate:masaru@media-lab.media.mit.edu:  "Silicon on Sapphire" by CLASH