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[74.102.50.111]) by smtp.gmail.com with ESMTPSA id bi6sm4067331qkb.29.2021.11.26.18.43.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 26 Nov 2021 18:43:10 -0800 (PST) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Alan Glasser Mime-Version: 1.0 (1.0) Date: Fri, 26 Nov 2021 21:43:10 -0500 Message-Id: <40B6AD3F-B40C-4F37-A802-51B1A39C0C51@gmail.com> References: <632335e1-c1ea-0eb8-2629-3e0829057da7@technologists.com> In-Reply-To: <632335e1-c1ea-0eb8-2629-3e0829057da7@technologists.com> To: "Charles H. Sauer" X-Mailer: iPhone Mail (19B74) Subject: Re: [TUHS] PL/I stuff - was: Book Recommendation X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tuhs@minnie.tuhs.org Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" On second thought, given that the Worldnet outage was late 1996, it was most= likely that the backups were to 8mm tape. Exabyte?! - Alan > On Nov 26, 2021, at 8:10 PM, Charles H. Sauer wr= ote: >=20 > =EF=BB=BFI haven't done anything with 9 track tapes for a long time, but I= used to help my father with his statistical research, processing what at th= e time seemed massive census and similar data sets on 9 track tape (using PL= /I on 370s at U. MO Columbia). Some of his tapes were quite old, stored in h= is basement and then his garage, but I don't recall problems reading any of t= hem. >=20 > IMNSHO, it all depends on the brand/formulation of the tape. I've been goi= ng through old audio tapes and digitizing them (https://notes.technologists.= com/notes/2021/08/21/making-private-1960s-and-70s-recordings-public/). Some a= re over 50 years old and still seem as good to me as when they were recorded= . Others, I can anticipate from the brand/formulation that they are going to= be trouble, if salvageable at all. Most surprisingly, unbranded and similar= budget tapes have survived as well or better than some of the high-priced s= tuff. A few days ago I tried a reel from 1968. I was dismayed by how many ti= mes it had been spliced, but replace the splicing tape and found it viable. >=20 > I have dozens of DDS-2, 3 & 4 cartridges from the 90s that I occasionally t= ry to read. I don't recall any of them failing. >=20 > (We probably should be COFFing this up.) >=20 > Charlie >=20 >> On 11/26/2021 6:30 PM, Larry McVoy wrote: >>> On Fri, Nov 26, 2021 at 07:23:07PM -0500, Dennis Boone wrote: >>> > In my experience 9 track tapes were not guaranteed to be readable aft= er >>> > some interval. In fact, a standard operations procedure was to copy >>> > important tapes to new media periodically. >>>=20 >>> There are always ways in which your backups can go wrong and not be >>> readable, and I'm not arguing that here. >>>=20 >>> But 9 track tapes have turned out to be pretty spectacularly long-lived.= >>> I've personally read tapes that were stored for 30+ years in >>> unconditioned spaces. >> Contrast that with the write only exabyte tapes. I lost some stuff to th= ose. >=20 > --=20 > voice: +1.512.784.7526 e-mail: sauer@technologists.com > fax: +1.512.346.5240 Web: https://technologists.com/sauer/ > Facebook/Google/Twitter: CharlesHSauer