On 8/28/15 9:25 AM, Jay Jaeger wrote:
Many/most 9 Track tapes (those from the early to mid-eighties until 1995 or so - what matters is the date of manufacture, not when they were written) have to be "baked" before reading, owing to "sticky shed syndrome". My experience with tapes earlier than that is that I can read them without baking them first.
Mid-80's are the worst, especially Memorex, and BASF, which everyone used because they were cheap. Whatever HP bought for their distribution tapes (probably Graham Magnetics) is very good. IBM tape is good too. DEC used crap tape for their distributions. Sadly, AT&T and Mt XINU ALSO used especially bad tape in the late 80's, so many of the Unix distributions I've been dealing with from them lately are so sticky even after baking that they are impossible to deal with. If you are going to be processing a lot of tapes, get a portable "tape scraper" (tape cleaner) and cover the blade. Retension the tapes with it at low speed after baking. The shed on the cloth covering the blade will tell you how bad the shed is. You can see a Graham Magentics portable cleaner in Paul's setup on the right. http://www.piercefuller.com/collect/proj.html I've processed over a thousand tapes in the past ten years, and their condition is not improving with time. Chuck has mentioned 3M Black Watch being bad, and I've started to see that now too, which wasn't the case in the past.
