Home Ch: 2 - Computers Data Storage Devices
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Chapter 2 - Hardware and Software

Data Storage Devices

The amount of electronic legal data piling up in law firms is staggering. Document management, calendars, multimedia, and the Web are causing storage to be fast growing and critical in your practice. There are a variety of storage solutions available and more are becoming available all the time. The Storage Network Industry Association (www snia.com) is focusing on standard protocols for storage tasks.

Data storage devices store data from operating and application programs onto a fixed media. Storage devices range from the basic  3 1/2 floppy disk, holding 720 kilobytes of data, to hard drives that hold upwards of 75 gigabytes of data. The type of media used to store your data will depend upon your needs and cost considerations. All storage devices measure their capacity in how many bytes they will store. The "pen drive" is replacing the floppy disk as the portable storage of choice.

Bytes. A byte is the basic unit of storage measurement. A byte is a group of 8 bits. A bit is a basic unit of information in a computer. Combining eight bits together to store the equivalent of one character or single digit number forms a byte. For example, the letter A, a single byte, is made up of 8 bits represented as 01000001. To represent a number greater than 9, two bytes are needed. The sequence of 8 bits to make up a particular byte is determined by an internal table called ASCII, American Standard Code for Information Interchange. The eight bits are represented within a computer by the changing voltage of an electrical current passing through a particular circuit.

The size of data storage devices, capacity of a disk, or the amount of computer memory can all be measured in bits and bytes.

Storage Unit

Number of Bytes (roughly)

Full Text Pages (double spaced)

One Byte












Floppy Disks. A floppy, also called a disk or diskette, is a removable storage device used to store computer files. Floppy disks come in one size - 3 ½”.  The smaller floppy, 3 ½” disk, holds between 720 kilobytes up to 1.44 megabytes, depending on the disk density. Before writing on a floppy disk, it must be formatted. After formatting, disks are inserted into floppy drives to transfer data and are generally used to transport data between two computers.

The standard file compression utility for floppies is the popular PKZip™ (DOS), and WinZip for Windows™ (www.winzip.com). Depending on the type of data, your files can be compressed to 1/5 of their normal size.

Hard Drives are devices used to write and read information that is stored on metal platters. They are usually inside the computer system unit. A hard drive’s storage capacity ranges from 20 gigabytes and beyond.

Hard drives must be formatted before using. Buy more than you can afford. A hard drive for a desktop should have a minimum of 80 gigabytes. Windows-based programs can easily use up to 20 megabytes of storage for a single program. Eighty gigabytes of hard drive space generally costs around $100 and the price will continue to drop as the size of the drive increases. Hard drives are becoming smaller, faster and less expensive. Removable hard drives are becoming increasingly popular to secure and protect confidential data and to provide easy sharing of data on laptops.

If your hard drive is running slow, consider running two utilities, scandisk.exe and defrag.exe,.that are available in Windows . Backup your data and run the scandisk.exe program first.

Below are examples of disk capacity and price on different cartridges.

CD-ROM. A CD-ROM (Compact Disk-Read Only Memory) is an injection-molded aluminized disc, which stores digital data in high-density microscopic pits. It is the same size as, and uses the same technology as musical CD disks. Once written to, the contents cannot be deleted or changed by the user. Multi-session CD-ROM allows for additional data to be added after the initial CD is “burned” with data. Many people are familiar with the compact disc as an audio device for playing music, but it can hold a staggering amount of text, graphics, images, animation, video, and sound data. The 4.72-inch compact disk stores approximately 650 megabytes (650 million characters) on a single side, compared to only 1.2 megabytes on a 3.5-inch floppy disk. The truly breathtaking fact is that the capacity of a compact disk is approximately 250,000 to 300,000 pages of full text or 15,000-document page images, (assuming 50,000 kilobytes per image).

The CD-ROM disk fits into a CD-ROM reader or drive that can be internal or attached to your computer. It can only read data off of the disk. It cannot write to or alter the data on a disk, unless the reader is also a CD-ROM writer. The CD-ROM is essentially another storage device, similar to your hard drive or floppy. CD-ROM offers optical advantages since they are not susceptible to head crashes, more durable than tape and allow for fast random access to data, have a storage life of more than 30 years, and are low cost.

CD-ROM Legal Applications for the legal profession include:

* Imaging - With the use of imaging, one can place up 15,000 document pages on one CD?ROM disk. Then, you can immediately view documents in your case without the need for PAPER and its inherent limitations. These digital documents can be used for witness preparation, depositions, trial, and so on.

* Legal Research -The major legal publishers have moved quickly to transfer their materials - case law, statutes, regulations, treatises, practice forms, and so on, onto CD-ROM.

* Video – DVD (see explanation below) CD-ROM’s hold at least 75 minutes of video on a CD-ROM. The value of CD-ROM video is the immediate accessibility of locating a certain segment of a deposition for direct or impeachment purposes in trial or to prepare a settlement video.

CD-ROM writers (CD-R) are now available that allow you to produce your own CD-ROM’s. CD-R which stands for compact disk – recordable is a CD format that allows you to write data onto a specially manufactured disk that can then be read by a standard CD-ROM drive. CD-R’s are becoming commonplace on new desktop computer systems. With the cost around $30 and the cost of a media at approximately 25 cents, each one can archive 650 MB for a small cost. CD-R discs can be read in most CD-ROM drives.

The process of “burning” a CD-ROM is relatively painless. A CD recorder uses blank CD’s that cost around 25 cents each and hold up to 650 megabytes of data. These discs contain a reflective layer of gold as well as layer of organic dye. Information is embedded onto the disc via a laser in the CD recorder. This is the so-called “burning” process. It is a somewhat delicate procedure because the recorder must transmit the information to the disk in a steady uninterruptible stream. If the data isn’t transferred from your computer’s hard drive to the recorders buffer quickly enough to keep pace with the laser, the system will abort the recording and you’ll have to discard your disk and start over.

Some features to consider:

* At what speeds can the recorder read CD-ROMs?

* At what speed can the recorder write data to a CD?

* What is the recorder seek time for reading and writing data (the faster the better)?

* What is the data throughput rate? Faster data throughput means the CD will be written faster.

* What is the recorder buffer size? The larger the buffer means it is unlikely that the recording process will be interrupted.

* What disc formats does the recorder support? Common formats include CD-DA, CD-I, CD-ROM XA, PhotoCD, Video CD, and CD-Plus.

* What are the recorder’s system requirements?

Purchasing a CD-ROM Drive/Reader. As the use of compact disk technology has expanded, the price of compact disk drives (readers) has been drastically reduced. Many brands of compact disk drives can be installed in an IBM-compatible PC at prices starting around $30. CD-ROM multimedia packages marketed by Creative Labs include the CD-ROM drive, sound cards, speakers, and a number of CD-ROM disks containing an encyclopedia and books.

There are a number of questions that must be asked when buying a CD-ROM drive:

* How fast is it? The speed of a CD-ROM drive is measured by its access time and transfer rate. A fast access time is important for text-based database search and retrieval applications. Access times range from 100 to 1,000 milliseconds. The average is 150 ms. A transfer rate of 150 kilobytes per second is required for multimedia applications using video and animation.

* Speed of the CD-ROM. CD-ROM speed has increased up to 30X and beyond. The speed of the CD-ROM determines whether the data transfer is seamless. For example, full motion movies can be viewed without any distortion in the pictures with the new speeds and transfer rates.

* Is it a Multi-Session Reader? Once a CD-ROM is “burned” with the document images or other material that you want, any of the widely available CD-ROM readers will read this CD-ROM. However, if you decide to add additional material to this same CD-ROM and reuse it, then a multi-session CD-ROM reader is recommended. Also, ask whether the drive reads multi-session Kodak Photo CD’s.

* Do I Need a Buffer? To display graphics, video, and animation in a smooth manner you need a consistent transfer rate of 150 kilobytes per second. Most new CD-ROM’s transfer data at 1000+ KB/sec. To maintain this rate, a drive should have a buffer rate of 32 kilobytes to 64 kilobytes. For text search and retrieval, a buffer is not needed.

* Does it use a SCSI (Small Computer System Interface) or Proprietary Interface? Most new drives use SCSI controller cards. Avoid non-standard proprietary interfaces. They limit you to the manufacturer’s technology and prices, and are generally slower than SCSI.

* Is it an Internal or External Drive? Internal drives fit into a 5-¼-drive bay. If it is an external drive does it attach through a SCSI port, parallel port or through a PCMCIA slot or PC Card? Which do you prefer and which one does your computer or laptop computer accept?

* Is Driver Software Included? The drive should include drivers from the manufacturer to recognize the controller. You’ll need Microsoft’s CD-ROM extension drivers.

* Can it Play Audio? Most CD-ROM drives can play musical audio disks. Audio software and headphones should be included. Will your sound card be compatible with the CD-ROM drive?

* Warranty and Support. Does the manufacturer offer toll free support? Do you pay the shipping charges if it needs to be repaired, or do they offer onsite support?

* Four disk changer. Should you purchase a four-disk changer? They are available for approximately $280.00

DVD. The Digital Versatile Disk (DVD) is replacing the traditional CD-ROM, and maybe the VCR. The DVD is the next-generation optical disk standard that has already been introduced. It has a storage capacity of 2.5 GB and above. It will store at least 90 minutes of video. The storage can potentially be increased to 18 GB since the new standard allows for double sided and double-layered storage. It is designed to be backward compatible, which will enable current CD-ROM’s to be played. However, it may be years before real-time video can be recorded on a DVD, which will lengthen the demise of the VCR. The price is approximately $100 and will be used primarily for movies. For the legal field, it will primarily be used to access image databases, video depositions, and any other legal application that requires a large amount of storage.

Magnetic Tape drives are portable and generally are used as backup devices, and cost under $100. The tape can hold approximately 100 megabytes of data up to 2 gigabytes and higher.

Magnetic-optical drives, like CD-ROMs, use lasers to read data, but also have the feature of writing data on the disk. They are fast, portable and are generally not expensive. There are two main types of magnetic-optical drives: WORM which stands for Write Once Read Many, and WMRM, which stands for Write Many Read Many. WORM drives can hold up to 2.6 gigabytes of data or more and are generally used to keep an unalterable audit trail. They only can be written on once but can be read many times. WMRM drives can be written to many times and read many times. These portable reusable drives make them an ideal backup storage media.

Backup Storage Devices. Hard drives eventually fail; so critical files should be backed up for later restoration of files. Backing up a hard disk requires copying files to a floppy disk or other storage device, such as a magnetic tape. Floppies, hard drives,  CD-ROM writers, magnetic tape, and other writeable optical disks are often used as backup devices for servers and PC’s. Backups are usually done on a timed rotation if the storage device is reusable. See Chapter 3, Disaster Recovery for more information on backup systems.


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