 | | Tape Drives: Still the Preferred Media for Data BackupsDespite all their features, however, hard disks are still machines invented by humans. They have a fixed life span after which there is a danger that they may go down anytime. This period is typically anywhere between three to five years. If a hard disk crashed due to any number of reasons hardware or software errors or natural or man-made disasters it can be catastrophic. All the data that you have stored on the disk can instantly become inaccessible and out of bounds. Total data loss causes many companies to fail each year as they cannot cope with the consequences they lose access to all their records and information and there are massive financial losses.
Therefore, the importance of taking regular data backups just cannot be over-emphasised. A variety of data backup media exist in the market, such as CDs, DVDs, USB drives and portable hard disks. However, the media that remains the most popular and effective for taking backups by companies is the tape drives. Just like hard drives rule in the world of primary storage for computers, tape drives rule the data archive market.
What are tape drives actually? Simply put, a tape drive consists of a large length of tape that is coated with a magnetic material, much like the platters of a hard disk carry a magnetic coating. This tape is wound around a couple of spools and the entire thing is enclosed in a plastic cartridge. The tape drive has a read / write head that is stationary and remains fixed at one place.
Unlike in a hard drive where the spindles rotate at the same place while the read / write head moves all over, in a tape drive it is the tape that has to move back and forth in front of the stationary head so that it can access data for writing, rewriting and deleting or saving. This kind of data access is called sequential access as the data can be only read strictly in sequence.
Tape drives use old technology of recording data, exactly like audio or video cassettes of yore. However, they are still quite popular and remain the best option for archiving a huge amount of important data. There are many reasons for this. For one, tape cartridges are quite cheap and easily available. No other data storage media can match the cost they offer in terms of per MB of storage.
The sequential data access has its benefits, even though the entire tape has to move back and forth before you can access a particular file. If a part of the tape gets corrupted, the entire data is not affected. You just have to cut that exact portion of tape, glue the ends together and you have the tape running again, offering you access to the rest of the data. Another benefit is that the tape cartridge that stores the data exists separately from the tape drive. In a hard disk, since the data-holding platters are built into the drive, any power surge can wipe out all the data.
A tape cartridge on the other hand has no parts through which electricity flows. In case of a lightning strike or power spike, only the tape drive is damaged, while the tape cartridge that stores the data remains safe and intact. It is easy to take a lot of tapes and store them in a safe place away from the computers. They are quite small and can be easily transported.
Data backup media has advanced in the last few years and has made rapid strides in terms of storage space. However, nothing can still come close to tape drives for the combination they offer of reliability and low cost for archiving a large amount of data for a long time. |
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| Information Security: Principles and Practice (Hardcover)
by Mark Stamp |  | As businesses and consumers become more dependent on complex multinational information systems, the need to understand and devise sound information security systems has never been greater. This title takes a practical approach to information security by focusing on real-world examples. While not sidestepping the theory, the emphasis is on developing the skills and knowledge that security and information technology students and professionals need to face their challenges.
Publisher: Wiley-Interscience (October 28, 2005)
Product Dimensions: 9.3 x 6.3 x 1 inches
Paperback: 416 pages | About the Book:
The book is organized around four major themes:- Cryptography: classic cryptosystems, symmetric key cryptography, public key cryptography, hash functions, random numbers, information hiding, and cryptanalysis
- Access control: authentication and authorization, password-based security, ACLs and capabilities, multilevel and multilateral security, covert channels and inference control, BLP and Biba's models, firewalls, and intrusion detection systems
- Protocols: simple authentication protocols, session keys, perfect forward secrecy, timestamps, SSL, IPSec, Kerberos, and GSM
- Software: flaws and malware, buffer overflows, viruses and worms, software reverse engineering, digital rights management, secure software development, and operating systems security
Additional features include numerous figures and tables to illustrate and clarify complex topics, as well as problems-ranging from basic to challenging-to help readers apply their newly developed skills. A solutions manual and a set of classroom-tested PowerPoint(r) slides will assist instructors in their course development. Students and professors in information technology, computer science, and engineering, and professionals working in the field will find this reference most useful to solve their information security issues.
An Instructor's Manual presenting detailed solutions to all the problems in the book is available from the Wiley editorial department. | About the Author:
MARK STAMP, PHD, is Professor of Computer Science, San Jose State University, where he teaches undergraduate and graduate-level information security courses. In addition to his experience gained in private industry and academia, Dr. Stamp has seven years' experience working as a cryptanalyst at the U.S. National Security Agency. | Book Reviews:
"Information Security: Principles and Practice presents information security concepts and practices insightfully in an easily comprehensible style. Although primarily intended as a college course resource, this book will appeal also to many security professionals. Highly recommended." (CHOICE, April 2006)
"The book is well suited for beginners, and contains enough introductory material on a variety of topics." (Computing Reviews.com, January 9, 2006) |
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