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Choosing a Tape Drive

Tape drives remain the leading technology used by organizations for backup and archiving. However, the plethora of tape drives on the market can make choosing the appropriate tape drive a confusing task. How do you select a tape drive that satisfies your needs without blowing the budget? The following are just some of the main factors to consider.

1. Capacity

Select a tape drive that has sufficient capacity to store your backups. Tape drives are able to compress data so that more data may fit on the tape, which is why manufacturers specify both a native capacity and a compressed capacity, usually with a compression ratio at 2:1. However, highly-compressed files such as those in video and sound formats are hardly compressible at all. For this reason, do not heed the specified compressed capacity when choosing a tape drive.

A good way to determine the size of the backup job after compression is to study logs of past backups. If these are unavailable, it is safe to assume that the data can be compressed at a ratio of 1.4:1, unless the hard drive contains an usually large number of highly-compressed files.

2. Transfer rate

The transfer rate of the tape drive is becomes important when there is limited "window of opportunity" in which backup jobs may run. It is often desirable for backups to take place during the night when network use is at its lowest.

Select a tape drive that is capable of completing a backup job within your window of opportunity. For instance, to back up 400GB per night, you will require a transfer rate of about 30GB/hour.

A little known fact about tape drives is that data must be supplied to them at a sufficient rate in order to keep them streaming, or else the tape suffers from start-stop motion. This motion severely degrades the life of the drive and tapes and the reliability of backups.

There are two usual reasons why tape drive are not be supplied with data at a sufficient rate. Firstly, the rate at which data is read from the hard disk of the server is insufficient. This rate is dependent on the sizes and locations of the files on disk and is generally unpredictable, but can be determined by the use of specialised software.

Secondly, if data is being transferred over a network of computers to a backup server, the network may be incapable of supplying data at a sufficient rate. The maximum throughput of a network is predictable and easy to measure, based on previous network performance.

Consider a network using 10BaseT Ethernet. This transfer rate through this type of network cannot exceed 10MB/s, so it is immediately apparent that a tape drive requiring 20MB/s is inappropriate.

3. Reliability and duty cycle

A simple way to gauge the reliability of a tape drive is to find out the Mean Time Between Failure (MTBF) as specified by the manufacturer. You should note, however, that the MTBF is usually specified at a certain duty cycle. For example, consider a Travan tape drive with a MTBF of 370,000 hours at 20% duty cycle. The drive will only have an average of 370,000 hours between failures if it is run less than 20% of the time (about 4.8 hours per day), and running the tape drive for any longer will significantly reduce the reliability of the drive.

4. Price

There is no point purchasing the highest-range tape drive if it's simply too expensive. Consider how much value-for-money the tape drive will give you. Are you willing to pay more for extra performance? Or do you need to sacrifice some performance to save on costs?

If you choose wisely, you should end up with a tape drive that fulfils your organization's tape backup and archiving needs, without blowing the budget.

Linus Chang is a backup expert and the lead developer of BackupAssist -- tape backup software that is simple and affordable, and perfect for small and medium businesses. Protect your Windows servers, including SQL Server and Exchange Server, to tape, REV drive, hard drive, NAS and more, at a fraction of the cost of other backup software.

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In The News:

Tracking the progress of the third party testing we at PES are coordinating along with U-Plug Products LLC, of their 2 kW U-Plug magnet motor that is a 24"x6" portable cylinder weighing 20 pounds, expected to cost 2,000 USD. We want to run it three times longer (21 hours) than what the best batteries available could provide. (PESWiki; February-April 2016)
Pre-launch video announces a new LENR website coming March 1, 2016 at http://LookingForHeat.com The video is very well done as an entertaining piece that hopefully will go viral. (Free Energy Blog; February 21, 2016)
It's not easy to find a qualified testing agency that is also willing to sign off on something that appears to defy our existing understanding of the laws of physics. U-Plug has agreed to allow for a group of us scientists, including at least 3 PhDs to go test their unit and publish our report. (PESN; February 20, 2016)
So that this is quite clear, this is a test on a Regular Torch. NOT the ELFE flashlight. This is to compare them. 2 x NiMH AA 1.2v Battery's in a Regular Torch with a Halogen Bulb. Load is 2.8v and 0.85amps. (PESN; February 17, 2016)
Video explains the scientific principles behind how the ELFE flashlight harnesses endless free energy from the environment (Earth's magnetic field), which works better in some regions than others. It also shows the insides the torch. Uses the word "antennae," as one of the components. (PESN; February 14, 2016)
"The OPhone contains a capacitor that directly powers our phone. During extensive use this capacitor may become discharged, however this capacitor is being constantly trickle charged by Orbo. So after a period of time the capacitor will be recharged and the phone will be functional again. In essence the phone is charging itself." (Free Energy Blog; February 13, 2016)
The company that has figured out how to harness the earth's magnetic field to produce usable power and has been selling the ELFE flashlight (two more customer reports), is now developing a 3 kW generator. In two weeks, they are holding a business meeting for international distributors. (PESN; February 12, 2016)
Illinois company is gearing up to manufacture a 2 kW (115 volts, 17.3 amps) magnet motor that is load-following, portable, 24"x6" tube, weighing 20 pounds, very quiet, with 3-year warranty but expected to last at least 20 years with zero maintenance. Third-party tested. MSRP 2000 USD, beginning March, 2016, through distributors. (PESWiki; February 11, 2016)
The government agent who worked on this technology five decades ago, that is similar to Professor Steven E. Jones' Joule Ringer, thinks it is conceivable that we could eventually scale this solid state technology up to have a device the size and price of an air conditioner providing 20 kw. (PESWiki; February 9, 2016)
Nagendra Singh in Mumbai, India, informs us that they have built five of these and have two running for customers presently, in the 40 kVA range. "Presently it is too [expensive], costing 3200 USD per kva below 30 kva." (PESWiki; February 8, 2016)
The SunCell is described as a solid state "Sun in a Box." A 200 kW module would weigh around 250 pounds, with energy production cost being around 1 cent/kwh, so return on investment could be ten days. They are expected to be available commercially by Q1, 2017. (PESN; January 6, 2015)
"Today I received my Elfe Flashlight and it works. Time will tell if it meets the claims of automatically recharging, when depleted. If it holds, the claims a real breakthrough in FE technologie would have been accomplished." -- German customer (PESWiki; February 6, 2016)
The phone battery indicator stays near full even with heavy usage throughout the day. (The battery is charged by the internal OCube that pulls energy from the wheelwork of nature, solid state). (PESWiki; February 5, 2016)
The capacity of the Proton-3ND (Proton -3 Nano Diffusion) battery is projected to be 44 times the capacity of lithium batteries. Electric vehicles with these batteries would have more power and much more mileage at no extra charge. (PESN; January 4, 2016)
HH2 water fuel cell creates pure hydrogen off a 9-volt battery. This was a big diesel HH2 cell that was tested on a 16-liter Cat engine for CARB testing; yet it ran on very low amps and a low 9 volts. (PESWiki; February 3, 2016)
A former U.S. Government worker describes his effort to bring to public awareness (by highlighting things presently in the public domain) energy and anti-gravity technologies that the government had operational 50 years ago but has kept from the public. (PESN; February 2, 2016)
Imagine an incandescent bulb that is actually more efficient than LEDs! Well, it actually exists (MIT) and it does so by recycling light. (Free Energy Blog; February 2, 2016)
SMBC-Comics.com has posted a fun spoof on our skeptics. (Free Energy Blog; February 1, 2016)
"OK, so a lot of people are asking what's the difference between an Orbo power cell and traditional batteries." Batteries store energy, Orbo generates energy, then trickle charges a lithium ion battery.] (Free Energy Blog; February 1, 2016)
Mr. Keshe is as misleading in the field of free energy as he is regarding me. That has been my experience the years I've been exposedto his work. He takes something and blows it so far out of proportion that it barely resembles the fact from which it was extrapolated into infinity. He demands: "Close PESWiki now." (PESWiki; January 31, 2016)
They have achieved solid state operation using an electromagnetic pump to spray the molten silver between the electrodes for the 1000/second continuous pulsing for continuous power production. (Free Energy Blog; January 29, 2016)

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