lib-MOCS-KMC364-20131012113553 230 I ournal of Library Automation Vol. 14/3 Septem her 1981 for member libraries and will demonstrate their system in mid-1981. OCLC data has been successfully transferred to many local circulation systems. RLGIRLIN RLIN does not anticipate offering local circulation services for member libraries. RLIN data has been successfully transferred to several local circulation systems. WLN WLN does not anticipate offering local circulation systems on their computer for member libraries. WLN data has been suc- cessfully transferred to local circulation sys- tems and an agreement has been reached with DATAPHASE, a computerized circu- lation system vendor, to discount purchase of their system by WLN member libraries. Public Online Catalogs Again, none of the bibliographic utilities under consideration currently support pub- lic online catalogs of an individual library's collection. A public online catalog requires further programming in order to make it easy for the public to locate materials of interest without extensive training; the bib- liographic utility's searching procedures are too esoteric to be used by the general public. As in circulation, issues of data transferabil- ity and full retrospective conversion of the UO Library's catalog are paramount. OCLC OCLC does not currently encourage public access to their database and does not support use of local online catalogs on their computer due to the tremendous demand for computer resources exerted by 2400 member libraries. OCLC and RLG /RLIN are participating in a study of user require- ments for a public online catalog. OCLC data has been successfully transferred to several local online catalogs, including Eugene Public Library's circulation and online catalog system, ULISYS. RLG!RLIN RLIN anticipates being able to offer pub- lic access to their database. They are partic- ipating in a study with OCLC of user re- quirements for such a system, but no date has been announced for the development of this capability in RLIN. RLIN data has been successfully transferred to a local pub- lic online catalog at Northwestern Univer- sity. WLN WLN does not believe that a local online patron accessed catalog should be provided through the WLN computer, even though they anticipate having such a capability within one year. Instead, they encourage libraries to develop local systems for public access to the online computerized catalog and to obtain data from the WLN catalog- ing system. The University of Illinois is adapting the WLN computer search and database management software to provide a local online catalog and computer- assisted instruction in its use for the public. Checklist for Cassette Recorders Connected to CRTs Prepared by Lawrence A. WOODS: Purdue University Libraries, West Lafayette, Indi- ana, for the Technical Standards for Library Automation Committee, Information Science and Automation Section, Library and Infor- mation Technology Association. INTRODUCTION A data cassette recorder connected to a printer port is an effective, low-cost method of collecting data in machine-readable form from display terminals such as the OCLC 100/105. It is important that a data recorder be used rather than an audio recorder al- though the cassette itself can be a good- quality audio tape. It is also important to note that the data recorded on the tape are not the same as the data originally transmit- ted to the display terminal, but are simply a line-by-line image of what appears on the screen. A typical installation will have a minimum of two devices: one attached to the display terminal to collect data, and one attached to a printer or an input device to another computer for playback of the data. There are more than 150 various data re- - cording devices on the market. This check- list is prescriptive in nature, outlining and describing those features that are necessary or desirable for a typical application. In ad- dition to features, environmental consider- ations are briefly mentioned along with in- formation for the purchase, lease, or rental of data equipment. FEATURES In general, featu.res must be compatible between all devices used for recording and playback in a given application. Some fea- tures that are desirable for certain applica- tions are unnecessary or inappropriate for others. 1. Recording Media The Phillips cassette is most widely used and may be interchanged be- tween the recorders of different man- ufacturers that utilize it. The car- tridge (either 3M or a vendor proprietary cartridge) is gaining pop- ularity because of its greater storage and transfer rates, but as yet is not widely used. 2. Code Most print ports on display terminals use ASCII (American Standard Code for Information Exchange) data code. The recorder selected should use the same. 3. Interfaces The cassette recorder has an "in" plug to accept data. This must be compati- ble with the print port on the terminal-usually RS232C. The "out" plug on the recorder sends the recorded data to a printer or to a com- puter. This interface should also be RS232C. 4. Recording Characteristics a. The number of tracks can vary from one to four. This is one of the factors that determine the amount of data that can be recorded on a single cassette. Four tracks are rec- ommended. b. Density also affects the amount of data that can be recorded. Usual densities are 800 or 1,600 bits per inch (bpi). c. Recording mode. Thereareseveral Reports and Working Papers 231 modes available. Phase Encoded (PE) is the best mode for data ap- plications. Non-Return to Zero (NRZ) is a popular mode, but has poor error recovery. IBM has a version called NRZI, which im- proves on NRZ but still is less reli- able than Phase Encoded. Other commonly found modes are Com- plementary NRZ and Ratio Re- cording. d. Recording format. There is a vari- ety of recording formats. To be as- sured compatibility with the ter- minal and playback device the format should be either ANSI (American National Standards In- stitute) or ECMA (European Computer Manufacturers Associa- tion) compatible. 5. Transmission a. Duplex. The recorder should have both full and half duplex avail- able. b. Data transfer rate (baud rate). Baud rate is usually switch- selectable from 110 to 9600. The recorder must be set at the same speed as the printer port on the ter- minal. The OCLC 100 and 105 terminals have a printer port baud rate selection switch that may be setat100,150,300,600,1200,and a meaningless 1800 baud. Select a recorder that has the fastest com- patible setting: 1200 baud is best. Data must be played back at a rate compatible with the receiving de- vice. 6. Tape Transport Characteristics a. Read/write speed is usually a func- tion of the baud rate. b. Non recording speeds. This feature is important for convenience. Fast forward and rewind should be available. One hundred twenty inches per second will rewind a cassette in about thirty seconds. c. Drive mechanism. Four options are available: capstan, pinch roller, servomechanism, or reel-to- reel. Pinch roller is the most pre- cise but reduces the life of the tape. 7. Packaging 232 Journal of Library Automation Vol. 14/3 September 1981 This feature can affect the price of the final configuration. If any item is listed as "separate," increase the total price accordingly. Components that can be either internal or separate are: controller, interface, or power sup- ply. 8. Remote Operation Some devices use ASCII control codes to trigger controls automatically. This is a useful feature, but the device must have a transparent mode switch, otherwise codes embedded in the data being recorded or sent may trigger un- desired operations such as rewind. 9. Operating Characteristics a. Rewind, fast forward, initialize, send and receive are all necessary operations and should be switch- controlled. b. Edit, auto program search, string search, skip, etc., are useful for word-processing operations but are of little use in simple data col- lection and transmission. c. Read backward is desirable for sort operations. d. Character mode, line mode, and string mode are useful for printing operations but of little use in data transmission. e. Online/offline should be switch- selectable. f. Simultaneous read/write is useful for editing operations. g. Direct block accessing is useful if there is a need to search for re- corded data but is not used in se- quential processing. h. Auto reverse is a useful feature for recording or transmitting more data than can be recorded on one side of a cassette. ENVIRONMENTAL REQUIREMENTS I. Humidity Range Humidity range should be 20 percent to 80 percent without condensation. Lower humidity will cause excessive static electricity. 2. Temperature Temperature range should be be- tween ten degrees and forty degrees centigrade. 3. Power Requirements Most recorders require a standard 115-volt alternating current at 47 to 63Hz. and draw about 60 watts. The circuit should be free from interfer- ence such as that caused by florescent lights. A transformer may be required in the outlet to guarantee even power. 4. Space Requirements The recorder usually can be stored on a desk top. It is important that the indicator lights be visible to the termi- nal operator to monitor its operation. PURCHASE I. Maintenance and Availability Ask how many drives the manufac- turer has installed to date. This may vary from a few hundred to one hun- dred thousand or more. Establish a maintenance contract with the com- pany or a local service bureau. It may be necessary to acquire a spare re- corder to use as backup. 2. Price Determine ahead of time what fea- tures you are actually going to use. Bells and whistles all cost money. A simple reliable recorder can be pur- chased for around $700. Multiple drive units and other features can run as high as $3,600.