Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcso!hpfcdc!paulp From: paulp@hpfcdc.HP.COM (Paul Perlmutter) Newsgroups: comp.sys.hp Subject: Re: Re: Any software support for Exabyte tape system? (Really: Why DAT?) Message-ID: <5570386@hpfcdc.HP.COM> Date: 13 Mar 90 21:11:40 GMT References: <174@tantalum.UUCP> Organization: HP Ft. Collins, Co. Lines: 86 PQP> The 7.0 release [...] supports the new 4mm product. The 8mm Exabyte PQP> product [...] is now being aggressively challenged by a variety PQP> of 4mm vendors - including HP. I doubt if you could claim it is PQP> the "defacto" standard. It merely had the lead, which I believe PQP> will erode quickly given the advantages of 4mm. In a very short PQP> time, 4mm should be out-selling 8mm. > Which advantages would those be? Slower transfer speeds, or smaller > capacity? I don't mean to sound snide (I'm not doing a very good job > am I? :-) Actually, you are sounding a bit snide. But I'll let it pass, and try to answer your questions. Exabyte marketing focuses in on size and capacity, but I claim that it is too simplistic a picture, and users are getting misled. Let me give an analogy: it's like buying a car and getting fooled into focusing on an engine that is bigger and faster, forgetting that you never needed engines of that size - and there is a whole lot more to a car than large engines. I think it is undeniable that 8mm has captured part of the market. But I think 4mm is better, it will become the defacto standard, and here to stay for some of these reasons: - 4mm is being aggressively marketed by both mechanism manufacturers and system integrators. *Already* we have 3.5" mechs on the market, half-height mechs, and the future is extremely bright with extremely low cost products in the very near future. Exabyte simply will not penetrate the low-end market because of their high-cost, form factor requirements. 4mm will totally dominate PC/Unix, other PC platforms, and low-end workstations! I claim in about one year Exabyte will be considered a "high-priced" solution! I claim that customers will want low-cost, high-reliability backup. This is what 4mm gives us. DAT is big enough, fast enough, and customers will focus in on the more important features such as: - lower cost - smaller form factor - partition support - fast search - Exabyte has some serious limitations: when you insert a tape into the mechanism, you can have a coffee break before it is loaded. Repositioning and ejecting cartridges is also unpleasantly tedious. Their 270 degree wrap angle causes reliability problems. (4mm uses 90 degree.) - Exabyte is the sole vendor of 8mm, and SONY is the sole manufacturer of 8mm. And that scares me. If Exabyte has a fire - poof, there goes production for a year. If SONY backs out for whatever reason, 8mm is dead. - Is 'size' the issue? I have only rarely seen systems that require 2 GBytes of storage. Remember too, that size varies dramatically on Exabyte tapes due to their implementation. So, 2 Gbytes is actually unusual, with smaller capacities very common. 4mm more reliably gives you 1.3 gbytes. Tapes are so incredibly cheap, that I find almost everyone merely archives their data onto a small portion of the tape and never reuses that tape! People continue to be misled by capacity: Exabyte requires 2 MBytes per file mark! Their error recovery is abysmal, and takes megabytes of capacity to recover. - About transfer speeds - Exabyte is a little faster. But let's look at the whole picture. I have seen users of Exabytes wait for hours and hours to recover a file. And this is no exaggeration. 4mm with fast-search will require a few minutes. The point is, I don't care how fast I transfer data as long as it is quick - since I do it at night. I care *very much* how long it takes to recover since I do that during the day! Transfer time is such a misleading concept. It's recovery time that is critical for me. And remember too: Exabyte claims 15 MBytes/min while DDS claims 11 MBytes/min. But when you consider the time cost in writing out file marks, or error-recovery for Exabyte, the speeds drop off. 4mm takes no data space for tape marks, and error recovery is light years ahead of 8mm.