ACRL News Issue (B) of College & Research Libraries September 1985 / 423 “Will m y disks go floo if I tak e them through ?” By P a tr ic ia B.M. B re n n a n Assistant Professor, Reference D epartm ent Rhode Island College a n d Joel S. S ilverberg Professor, Program in Com puter Science Roger W illiams College The effects of a magnetic security system upon magnetic microcomputer storage media. C om puter diskettes have become as common a campus commodity as syllabi and chalk. Students and faculty think nothing of popping them in back­ packs and briefcases and transporting them every­ where. Most com puter users are aw are th a t disks have certain h an d lin g and care requirem ents. Along w ith dust, fingerprints, heat and pressure, both the library and com puter literatures resound w ith th e c o m m a n d m e n t: av o id m a g n e tic fields.1’2’3 Prom pted by concern expressed by colleagues which was reflected in a question to American L i­ braries “Action Exchange”4 and in reports to L i­ brary Hotline5,6 concerning magnetic field damage 1R alph R. D ic k m a n , “ C hoosing a R eliable Floppy Disk,” Interface Age 9 (June 1984):70-72. 2Helen P. H arrison, “Softw are on the Shelf: Com puter Materials in the L ib rary ,” Audiovisual Librarian 9 (W inter 1983):45-48. 3Robert M. Mason, “All About Diskettes,” L i­ brary Journal 109 (March 15, 1984):558-559. 4“Äction Exchange, American Libraries 14 (De­ cember 1983): 711. 5“More on Magnetic Field D am age to Video­ ta p e s ,” L ib ra ry H o tlin e 13, no. 15 (April 16, 1984):4. 6“More on Possible D am age to Magnetic Ele­ ments from Security Systems,” Library Hotline 13, n o .17 (April 30, 1984):7. to library media (including softw are), a series of ex­ perim ents was designed to determ ine the effect of a m agnetic security system (Tattle Tape model #31) on a standard 5 inch minifloppy disk. Romeo and W atstein have succinctly outlined the basic structure of the 3M T attle Tape security system: The T attle Tape system operates on an electromag­ netic principle. A thin pressure-sensitive detection strip is hidden in the book spine or between the pages in the gutter of a book or periodical. An exit­ way is formed by a detection post and lattice-like sensing unit which emits an electronic detection field from the floor to the top of the screen? At the heart of the T attle Tape Detection System is the T attle Tape Detection Strip. This device is a small, thin, flexible, metallic strip which generates an electrical signal when stim ulated by a low fre­ quency alternating electromagnetic field.8 In addition to the exit gate sensor and the detec­ tion strips, the third component of the system con­ sists of an activator/deactivator unit which mag- 7Louis J. Romeo, “Electronic Theft Detection Systems, Part I: Small College L ibraries,” Library & Archival Security 2, no.3/4 (1978):1, 7-14. 8Sarah B. W atstein, “Book Mutilation: An Un­ welcome By-Product of Electronic Security Sys­ tem s,” Library & Archival Security 5, no. 1 (Spring 1 9 8 3 ):ll-3 3 . 424 / C&RL News netically sensitizes and desensitizes the detection strips as p a rt of the circulation process. W e considered the question: under w h at cir­ cum stances w ould the security system and any com puter disks normally interact? We identified three possibilities. Repeated exposure to the exit gate sensor would be norm al for any patron m ak­ ing frequent use of the library. Second, it is possible th a t disks m ight be exposed to sensitized or “hot” m agnetic strips in the books used w ithin the build­ ing. W e also investigated an extreme case of pro­ longed exposure to the exit sensor, although this is unlikely to occur. F in ally , th e possible conse­ quences of accidental exposure to the activator/de­ activator unit were examined. An Apple II com puter was used to create a se- qential text file, recorded on a Verbatim (Datalife) single density m inifloppy disk. T he V erb atim brand was chosen because of its widespread use.9 The file contained 3,200 repetitions of the norm al alphabetic sequence: A through Z. A verification program was then w ritten to check th a t disk after each experiment to see if any data w ithin the file had been lost, dam aged, or altered. The verifica­ tion program contained a “stan d ard ” alphabetic sequence against which each of the 3,200 alphabets was checked. The program recorded how m any se­ quences m atched its standard and how m any failed the comparison. Thus, any deviation from the ex­ pected sequence of 83,200 characters (3200 x 26) would be detected and recorded. Experim ent I involved the help of a student assis­ ta n t who carried the d ata disk past the sensor 100 times, as if exiting the building. The verification program showed no loss of data. In Experim ent II, a sensitized book was chosen at random from the collection. The Circulation D epartm ent checked the book to make sure the de­ tection strip was “h o t.” The d ata disk was then placed inside the book and left undisturbed for 10 hours. As before, the verification program revealed the d ata to be unaltered. Experim ent III was designed to test an extreme situation: one unlikely to occur in practice. P artic­ u la r concern h ad been expressed by some col­ leagues about carrying their disks past the exit sen­ sor on a daily basis. The d ata disk was attached by its paper jacket to the exit gate sensor. It was left in this position seven days. The gate rem ained in con­ tinuous operation and continued to detect a num ­ ber of sensitized books while the disk was attached to it. The verification program once again showed no alterations of the 3,200 alphabetic sequences during the 168 hour trial. The first three experiments considered normal interactions between the disk and the security sys­ tem. A less usual hazard is the accidental exposure of a com puter disk to the activ ato r/d eactiv ato r unit. The d ata disk was “accidentally” left as a b o o k m a rk in a book w h ic h w as th e n p assed 9See note 3. through the activator/deactivator unit during rou­ tine check-in procedures. The verification p ro ­ gram was unable to read the disk at all. F u rth er ex­ am ination of the disk by other program s revealed extensive dam age to the operating system, disk di­ rectories, and data. For all practical purposes, the data disk was rendered unusable. Conclusions This series of practical field tests supports the statements of Gene Heltemes, 3M engineer, th at the T attle Tape system has “such a weak magnetic field th a t it could not possibly dam age a tape being carried through it.”10 Neither sensitized books nor the detection mechanism of the exit gate affected the type of disk used in these experiments. It ap ­ pears th a t com puter disks may be carried and used in the library w ithout undue concern. Accidents, of course, can still happen. The one th a t seemed most likely to occur (exposure to the a c tiv a to r/d e a c tiv a to r u n it d u rin g check-in or check-out) co n stitu ted our fo u rth experim ent. Such exposure did indeed render the disk unusable. It is the opinion of the authors th a t data disks, or in fact any magnetic m edia, should never be brought into close proximity w ith the activator/deactivator mechanism because of the dem onstrated effects of its strong magnetic field. ■ ■ 10See note 6. New AAAS prize The American Association for the Advance­ m ent of Science has created the AAAS-Philip Hauge Abelson Prize in honor of a former editor of Science. The $2,500 prize will be aw arded annually either to: 1) a public servant in recog­ nition of sustained exceptional contributions to advancing science; or 2) a scientist whose career has been d istin g u ish e d b o th for scien tific achievement and for other notable services to the scientific com munity. The first Abelson Prize will be aw arded at the 1986 AAAS Annual Meeting in Philadel­ phia. Each nom ination must be seconded by at least two other AAAS members. Since ALA is an in stitu tio n a l m em ber of AAAS, ALA members may subm it nominations to Roger Parent, ALA D eputy Executive D irec­ tor, 50 E. H uron St., Chicago, IL 60611. Nominations from ALA should be received at AAAS no later than December 31, 1985. The follow ing in fo rm a tio n should be included: nominee’s nam e, institutional affiliation and ti­ tle, address, and brief biographical resume; statem ent of justification for nom ination; and nam es, identification, and signatures of the three or more sponsors. The w inner will be se­ lected by a seven-member panel appointed by the AAAS b o ard of Directors.