Conference ssag::ask_ssag

    
    I'm a DLT guy, so you know what I'm going to say.. 8^).
    
    But really, from the cartridge reliability point of view, DLT tape is
    propably one of the best. Capacity wise it is better than 3480/3490
    and 0.5". Reliability wise it's far better than 4mm, 8mm, and QIC.
    So I'll say overall rating it's on top.
    
    T.
    

	"Buy DLT since it offers the best combination of performance,
	capacity and reliabily."

	Then explain that we offer the others because that's what
	some customers want to buy and if we didn't have it, they
	would just buy it somewhere else and probably their systems
	as well.  Even allowing for reliability problems with many
	older 8mm tape systems, many customers prefer because of
	media cost.  They feel the performance is adequate and the
	capacity sufficient.  They are being driven by the cost per
	tape.  The same may apply to RDAT, though I've never thought
	the performance adequate.  The size is convient though.

    By default I have to say DLT.  Having taught the hardware for the TA90s
    I can say the media and hardware are robust, however the TKZ60/1/2 are
    not nearly so well made.  The DAT drives are all (MY OPINION) cheaply
    made and probably adequate for very small systems.  We have a customer
    who uses Transition Technologies Inc.  (aka) CTS 8510 hxl drives, over
    30 of them on contract.  We have had to swap/repair all of them more
    than once in just under a year.  
    
    TZ85/6/7 and the family have only the problem with the leader, and we
    just replace that.  
    
    Dave

    
    
    ......Also lately I have noticed a lot of Quantum DLT4xxx (looks
    like a TZ8XX) on Suns and HPs and even COMPAQ......
    
    I take the opportunity to let them know that it came from DIGITALs
    lowly TK50 product....
    
    

On the public mailing list with various people giving input
on which tapes to use (many are not Digital customers), DLT
got the best responses.  Some people mentioned how happy
they were after switching from 8mm/4mm.  Most noted the better
reliability an price per MB as factors.  Some noted that it
could be tough to convince management to make the shift, but when
they did they immediately reduced the time spent on tape/drive
problems.

I know testimonials are not proof of anything, but a few years
ago one would have seen the conversation center on 8mm and 4mm.
  

    There is no one tape product which will adequately cover a full line of
    computers. PC's don't usually justify a DLT drive - it can cost more
    than the PC.
    
    That said...
    
    DLT is a performance/reliability leader, High duty cycle applications.
    Large libraries and loaders are available.
    
    DAT is useful for lower duty cycle apps, lower cost and capacity, lower
    media cost. Transfer rates are near 1MB/sec on the new drives. 3.5"
    form factor drives are the norm. Media wears out after a couple of
    hundred uses. Due to the lower costs, it works well as a transfer
    medium, or a small server backup device.
    
    QIC is even lower end...Cartridges need retensioning occasionally, they
    have issues with appending data, but they do work if the SW knows how
    to handle them.
    
    I don't recommend the current 8mm products to anyone, unless they need
    media compatibility. There have been serious media wear and data
    reliability issues with it in the past.
    
    There's a new 8mm technology coming soon which may compete well with
    DLT, but it is totally incompatible with current 8mm drives. It also
    has none of the above mentioned problems.
    
    They all have a place. 
    
    What class system is this customer using?
    
    Chris
     

	Tape formats ...


	QIC ( 1/4 inch cartridge ) - low cost, sold to PC users,
	   used for data interchange with old SUN, IBM, and HP workstation
		Digital TZK10, TZK11, TZK12

	DAT ( 4mm ) - based on audio tape format, very low media cost,
	    drives are 3 1/2" form factor, designed and built by many companies.
	    started at 150 KByte/sec - 1.1 GB per tape, now 600 KByte/sec - 
	    16 GB per tape. Used on workstations and PC servers.
		Digital TLZ04, TLZ06, TLZ07, TLZ09

	8MM ( exabyte drives ) - ALL 8mm drives are built by Exabyte.
	    drives are 5 1/4" form factor, Sold by many companies, design
	    based on video 8mm, low media cost.
		Only sold in special cases. Sold by special systems group
		as TKZ08 TKZ09. Drives fail in heavy use.

	AIT ( New Sony format ) - not released yet, comming this spring.
	    drives are 3 1/2"  design and built by Sony
	    25/50 GB per tape  at 3/6 MB/Sec.

	DLT ( 1/2" media ) - High speed, very reliable, built for data center use.
	    drives are 5 1/4" design and built by Quantum
	    35/70 GB per tape at 5/10 MB/sec.

	3480/3490 ( 1/2" media ) - high speed, low capasity per tape
	    used for data interchange with IBM systems. Getting  old.
	     I don't expect to see them much longer.



				Steve P.

More on tape formats ...

CSS have released the TKZ90 product. This is effectively an OEM version of the 
IBM Magstar i.e. uses the 3590 cartridges.

In the previous replies the speed of the DLT is mentioned as 5MB/sec native 
with a cartridge capacity of 35GB uncompressed. The TKZ90 has a capacity of 
10GB (20GB per cartridge soon, in a few months) uncompressed and a transfer 
speed of 9MB/sec native. Combining this tape drive with libraries, you could 
have a very high speed backup solution.

So with a combination of TKZ90, a library and some backup software (like NSR 
or even Alexendria (from spectralogic)), you could have the basis for a very 
high end backup solution.

I agree with the previous notes that the capacity of the 3480/3490 cartridges 
was limited, but I do think that the capacity of the 3590 is much more usable. 

So what does the panel think about the 3590 technology and the TKZ90?

	Price, bandwidth, interchange-capability, and capacity are 
	interesting attributes; in the low end, those may be enough to 
	decide.  For high-end folks, I note that:

   1.	For some users, robustness matters more than any of the above.
	I expect the TZ89, like the other DLT drives, to have a lower
	probability of undetected data errors than any other drive.

   2.	Mainstream products (like the TZ89) tend to be more rigorously
	qual'ed than low-volume products (like the TKZ90).

   3.	Mainstream products tend to have better post-sales support
	(hardware and software) than low-volume products.

	    {Please - I'm not knocking CSS; just pointing out the 
	     implications of economic reality.  No free lunch, eh?}

	So, you know where my heart is.  But, the right answer depends on
	the customer's priorities.

	{Personally, I bought a QIC-80: slow, unreliable, poor tape life, 
	 drive needs too-frequent cleaning, requires operator attendence, 
	 lousy documentation, obscure GUI, content-free backup help files,
	 vendor's (long distance non-toll-free) hotline way below 
	 room-temperature, no discernible error-handling and no soft-error 
	 reporting, low capacity and no robot; in short, everything I
	 always hoped against.  But cheap.}

Cheers, Bob