How to Select and Use Data Entry Devices

In days of old

When the keypunch was bold, Shared processors weren't invented.

You could pick any gem Made by IBM,

And know you'd be contented.

Underneath the seeming nonsense of the preceding jingle lies considerable sense. A simpleton can make a proper decision when there is only one choice to make. In the embryonic days of computer technology, the punched card was the only effective data entry medium for com-mercial applications and paper tape was the preferrred method of input for scientific applications. Such was the extent of decision-making that anyone was called upon to perform.

We are all proud of the progress that data processing has made since the toddling period of the 50's and early 60's, but with progress comes a variety of options - and headaches. Today the data processing manager may still opt for an IBM product, but he should at least give serious consideration to whether it is really the best selection for his particular application environment. As the pressure of cost competitiveness grows fiercer, the likelihood of feel-ing totally content with any data entry decision grows smaller. One should have the feeling that something better lies just over the horizon. The guidelines appearing in this report are intended to put the analyst on the right track and increase his awareness of the overall data entry opportunities awaiting him.

Let us catalog the various data entry devices that now exist. In the context of this report, the term "data entry devices" refers to equipment or contrivances that capture data at its source and/or convert source data in human-readable form (handwriting or printing) into any of a variety of codes that can be interpreted by a computer system. These devices can either enter the data directly into a computer or record the data on an intermediate medium for subsequent entry into a computer. Certain data entry devices perform the subsidiary function of creating an audit trail, which is essentially a printed record of the data actually received by the data entry device.

The current data entry devices can be categorized as follows:

• Card punches and verifiers.

• Keyboard to paper tape devices.

• MICR readers.

• Mark readers.

Selecting a system to resolve your computer input bottleneck should involve more than just trend-following. There are many different ways to feed a computer, and each has distinct advantages and disadvantages. This report pre-sents a comprehensive look at all the available data entry devices and how to select and use them effectively.

• Optical character recognition (OCR) devices.

• Industrial data collection devices.

• Point of sale (POS) devices.

• Voice response systems.

• Interactive remote terminals (including CRT minals, typewriter terminals, and "intelligent" ter-minals).

• Keyboard to tape/disk devices (including keyboard to compatible tape, keyboard to cartridge or cassette, keyboard to diskette, keyboard to disk, and multi-station keyboard to tape or disk).

The prospective user of data entry systems should attempt to familiarize himself with these basic types of equip-mentas his first step toward reaching a decision. In

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An Entrex System 480 CRT keystation is shown in front of the compact central control group. This multi-station key to disk system is well respected by data entry professionals.

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addition to this report, an excellent way to learn about specific classes of data entry devices is to read the in-dividual product reports in the Peripherals section of DATAPRO 70. The Index lists each product report under its specific name and under one or more generic headings (e.g., keypunches, key-to-tape recorders, programmable terminals, etc.). The feature reports on Optical Readers, CRT Display Terminals, Typewriter Terminals, and Voice Response Systems will prove informative as well.

Before discussing the various categories of equipment in the preceding list, let us first establish a background of available data entry media and their properties. Some-times this knowledge alone suffices to dictate a particular equipment choice. For example, in a typical banking application, such as demand deposit accounting, the MICR-encoded document is the obvious input medium to use. This decision, in turn, determines the type of data entry device to select for that application (namely, an MICR sorter/reader, or perhaps an optical reader equipped to read the MICR font.)

Presented below are eight properties of media to consider when evaluating the type of data input media to use in particular applications. Following that is an evaluation of the more common types of input media in relation to these properties. Having a clear idea of the relative merits of the various kinds of media, the user can easily relate these media to the needs and overall characteristics of his particular applications. Then the user can begin evaluating the particular classes of data entry devices in terms of media which seem suitable for the selected applications.

Properties of Computer Input Media

These are eight principal properties to consider when evaluating computer input media.

1. Sensibility. Can the medium be read by machine only or by both machine and humans? For some applications, such as text copy or turnaround docu-ments, it is advantageous for the data to be easily readable by human eyes.

2. Reusability. Can the data recorded on the medium be erased and replaced or changed by new data, as when correcting an entry error?

3. Storage Restrictions. Can the medium store more than one record? Is record length restricted to a fixed maximum number of characters?

4. Speed Restrictions. What is the maximum reading speed of the recorded medium?

5. Sorting Capability. Can the medium be sorted prior to computer input?

6. Handling. Can the medium be easily handled once removed from the machine? Does it easily sustain

damage? Are there storage requirements to consider such as space (storage cabinet size), temperature, and humidity conditions?

7. Cost. What is the cost per character of storage?

8. Applicability. Does the medium exhibit unique characteristics suitable for special applications?

Common Input Media

How do the conunonly used input media rate with respect to the listed entries?

Punched tape. Can be read by humans only if the reader is familiar with the specific data code. Punched tape cannot be erased and errors cannot be corrected, but known errors can be identified by delete codes punched into the tape. Standard data density is 10 characters per inch.

Record length can vary up to 120,000 characters for a 1000-foot roll. Reading speed typically peaks at 1000 characters per second but can go as high as 3000 charac-ters per second when reading strips. The punched tape cannot be sorted prior to computer intput, but merging can be performed.

Punched paper tape normally comes in 1000-foot rolls;

standard tape widths are 11/16-, 7/8-, and I-inch (the I-inch size is used more heavily than the other sizes). Tape bases other than paper include Mylar and metal for special applications. There are no set environmental requirements for temperature and humidity. Based on prices quoted to Datapro, I-inch paper tape costs about 0.83 cent per 1000 characters. Costs rise sharply for Mylar and metal tape.

Punched cards. Can be easily read by humans when inter-preted (Le., when the characters are printed above the punched codes). Punched codes cannot be erased except by affixing patches over the error punches. Record length is limited to 80, 90 (UNIVAC), or 96 (IBM System/3) characters. Card reading speeds currently range from about 20 to 2000 cards per minute, with most instal-lations falling into the 200 to 1000 cpm range.

Cards can be sorted manually and by machine, and can be merged by machine prior to computer input. Cards are normally ordered in cartons of 10,000 cards each. There are set environmental requirements for temperature and humidity, and if they are violated, damaged cards and operating difficulties can result. Cost per thousand charac-ters of storage is about 7.3 cents.

The uniqueness of punched cards lies in the discreteness of each card as a unit record and the convenience of manipulating it. This allows easy addition, deletion, and rearrangement of records, and provides a manual reference to individual items. When interpreted, the data punched into the card can be quickly read by humans. t::::

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How to Select and Use Data Entry Devices i:> Magnetic tape. Can be read by machine only. Magnetic

tape can be easily erased and therefore must be carefully safeguarded against unintentional erasure. Errors can be corrected without disturbing adjacent data. Data record-ing densities commonly used are 200, 556, 800, and 1600 characters per inch. In March 1973 IBM introduced a new technique called Group-Coded Recording (GCR) that enables data to be written at a density of 6250 charac-ters/inch. Record lengths are variable.

Typical reading speeds vary from 15,000 characters/

second at the lowest density to 320,000 characters/second at a density of 1600 characters/inch and to 1,250,000 characters/second at 6250 characters/inch. The contents of magnetic tape cannot be sorted before serving as com-puter input, nor can individual tapes be merged. (Tape contents, of course, can be dumped to a disk and sorted under processor control, and partially recorded tapes can be played into a pooler that records a new merged tape.) Standard magnetic tape reel sizes are 7-inch (600 feet), 8.5-inch (1200 feet), and 10.5-inch (2400 feet). Environ-mental restrictions are imposed for magnetic tape storage, but they allow wide temperature and humidity ranges.

Cost per character of storage varies according to the supplier and the quality of the type. In slow-moving, low-density tape applications, poorer grades of tapes may be quite satisfactory. Assuming the use of good-quality tape, and supposing that the tape is ordered in batches of 100 to 999 reels, the approximate cost of storing 1000 characters when the recording density is 200 bits/inch is 0.3 cent. Disregarding record-length and gap-size con-siderations, the cost of storing 1000 characters at a den-sity of 1600 bits/inch is roughly 0.035 cent. At the new density of 6250 bits/inch, the cost can go down to about one-fourth as much.

Disk Packs. Can be read by machine only. Since magnetic disk packs can be easily erased, they must be safeguarded against accidental erasure. Errors can be corrected without disturbing other data.

At present users can choose from a number of disk drives and disk packs. The IBM 1316 Disk Pack or its non-IBM equivalents, for example, contains 6 disks and provides 10 recording surfaces; it can store up to 7.25 million bytes. The IBM 2316, or equivalent, contains 11 disks and provides 20 recording surfaces; it stores up to 29.17 million bytes. The IBM 3336, or equivalent, has 12 disks and provides 19 recording surfaces; Model 1 stores 100 million bytes and Model 11 , which is constructed in exactly the same way except for a double density of cylinders compared with that of Modell, stores up to 200 million bytes. The 3348 Data Module stores 34.9 million bytes in Model 35 and 69.8 million bytes in Model 70. A new-comer to mass storage, the floppy disk or diskette (23FD-11), stores 653 thousand bytes. It is simply a flexible Mylar disk, 8 inches in diameter, enclosed in a

plastic envelope. This envelope remains stationary in the disk drive mechanism while the disk spins freely. Cutouts in the envelope allow access to the tracks for the read/

write head and sector-sensing devices.

Based on IBM prices, the following figures show the variation of storage costs for each 1000 bytes. For the IDM 1316, which costs $360, the amount is 4.96 cents.

For the IBM 2316, which costs $525, the amount is 1.8 cents. For the IBM 3336 Modell, which costs $1000, the amount is 1 cent. For the 3336 Model 11, which costs

$1150, the amount is 0.58 cent. For the IBM 3348 Model 35, which costs $1600, the amount is 4.6 cents. For the 3348 Model 70, which costs $2200, the amount is 3.1 cents. The price of a diskette is about $6, and the cost of storage per 1000 characters is 0.92 cent.

It should be recognized that the lengths of records stored on disks can vary in accordance with the formats imposed by the controlling software. The formatting may not make full use of the available capacity, in which case the cost of storage rises proportionately. Some sample disk reading speeds, exclusive of access times, are 156,000 bytes/second for the IBM 2311 Disk Drive, 312,000 bytes/second for the 2314, and 806,000 bytes/second for the 3330. Environmental constraints governing the use of disk packs are not stringent.

Once the user has determined the media requirements of his applications, he can begin to examine the many avail-able classes of data entry devices. In the following dis-cussion these classes are explored and evaluated. Special attention is given to classes or devices that are not fully treated elsewhere in DATAPRO 70.

Card Punches and Verifiers

Certainly the most common form of data entry device in use today is still the keypunch machine that produces the 80-column punched card. The keypunch began to be widely used as early as the 1920's and 1930's. During the 1950's its usage began to multiply dramatically, and by the mid-1960's, approximately 500,000 keypunches were busily producing mountains of punched cards. This rapid growth remained unchallenged until April 1965 when Mohawk delivered its first keyboard to magnetic tape data recorder.

Improvements, enhancements, and extensions to the basic Mohawk innovation, including the multiple-station key to disk concept, have since mushroomed in the form of diverse data entry products from at least 50 companies.

Most of these keyboard to tape devices are aimed directly at the keypunch replacement market.

Even after receiving its first challenge, however, the key-punch has continued to be a heavily used data entry device, and will evidently remain so for years to come.

Ultimately, its popularity should gradually decrease in i:>

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terms of both the number of installations and the per·

centage of the total data entry devices in use.

The durability of keypunches is partly explained by the fact that they are "old friends" to most computer pro-fessionals. To many old-timers, the punched card and data processing are almost synonymous. The lengthy pre-computer years of electronic accounting machines (or

"tab" equipment) makes this attitude understandable.

Punched cards are comfortable. To the average person (computer professionals included), it is natural that data be contained in punched holes on a card - holes can be seen. On the other hand, many people feel that magnetic patterns in tape or disks or cores (of all things) are intangible and therefore disquieting. Besides, there is both psychological pleasure and operational reassurance in actually seeing cards speed through the machines.

The death knell for punched cards has sounded many times. First OCR rang the bell, and more recently key-to-tape and its off-shoots have also sounded the bell. Never-theless, throughout all of this tolling card manufacturers continued to make more cards. They are still making them.

Consequently, Datapro does not hold with data entry experts who dismiss the punched card as obsolete and profess contempt for anyone who chooses it. But our support of cards is qualified. We contend just as strongly that, for many data entry environments, punched cards are in fact outmoded and a processor-controlled method of data entry would be much more productive. Clearly, a paradox exists. We have no doubt that in many environ-ments the keypunch and the punched card remain the wisest possible choice. We also have no doubt that in

The widely used UNIVAC 1710 VIP keypunch is one of several units on the market today that boast of electronic operation and data buffering. In addition to its role as a keypunch, the 1 710 also acts as a verifier and an interpreter.

many other situations their choice is poor and reveals backwardness of outlook.

When is the keypunch a wise choice? The following char-acteristics would seem to favor keypunches: (1) need for a small number of data entry stations; (2) need for a rela-tively small number of program formats, say, no more than about 10; (3) ability to work effectively with 80- or 96-character records; (4) availability of strong editing procedures in the central computer; (5) acceptability of subsequent discovery of errors by the central computer rather than early discovery in the data entry process; (6) absence of a need for rapid and systematic search of the recorded data records; (7) absence of a need for im-mediate printouts; and (8) absence of any outstanding personnel disciplinary problem.

These are a lot of conditions, but part of the data entry paradox is that probably more environments exist that satisfy these conditions than that do not. What these conditions really say is that if the data entry activity is relatively straightforward and not overly voluminous, then the tried and true keypunch with its directness and sim-plicity might well be the best choice to make. (By the

"best" choice, we mean the most cost-effective.)

This rally to the defense of keypunches is not meant to be all-inclusive. Certain keypunches have recently been out·

fitted with buffers and electronic functions that bestow in elementary form many of the basic advantages of pro-cessor-controlled data entry systems. To be sure, when sophisticated editing and validation procedures must be imposed upon the entered data, the keypunch cannot compete. Nevertheless, in many straightforward situations the cost of processor/controlled systems is prohibitive and the latest electronic keypunches can serve quite effectively.

An impressive example is the Tab Products Punch·

Verifiers and Interpreters. The keying of these devices is electronic and silent. As characters are keyed, they are stored in a data input buffer, and no action is performed on the card. Prior to the keying of the 80th character, the operator can backspace and make any desired corrections to the data in the buffer. When the 80th character is keyed, the entire record is transferred to a data output buffer and the card is automatically punched. Without waiting, the operator proceeds to the keying of the next record. The previously keyed record is retained in the output buffer so that duplications can be made from it. In short, all of the familiar keypunch characteristics are retained.

The Tab Punch-Verifier also incorporates a program buf-fer, which can store 5, 10, or 31 levels, depending on the model. Hence, the Tab device can store many more than the two program levels of the old-fashioned mechanical keypunches that rely on drum cards. The formats, further-more, can be automatically sequenced. This feature is

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How to Select and Use Data Entry Devices t> extremely valuable when a business form with successive

lines that differ in organization must be entered. The Tab device permits such a form to be entered in sequence without manual intervention by the operator.

Another useful feature of the Tab Punch-Verifier is

Im Dokument Contents of Volume 2 datopro (Seite 133-150)