239:
350:, which incorporated two internal drives. These were very similar to the ZX Microdrive, but used a different logical format, allowing each cartridge to hold at least 100 KB. Mechanically the drives were similar, however, they ran slightly slower and had a take-up acceleration start instead of the instant start of the ZX Spectrum drives, putting less strain on the cartridges. The QL also included a Microdrive expansion bus, allowing the attachment of up to six external QL Microdrives. These were never produced, probably due to lack of demand. It was, however, possible to connect ZX Microdrives to a QL by putting a twist in the cable.
339:
121:
22:
196:
993:
319:. It was possible to "expand" the capacity of a fresh microdrive cartridge by formatting it several times. This caused the tape to stretch slightly, increasing the length of the tape loop, so that more sectors can be marked out on it. This procedure was widely documented in the Sinclair community magazines of the 1980s.
329:
The system acquired a reputation for unreliability. The tapes stretched during use (giving them a short life span), eventually rendering the data stored unreadable. Also the "write protection" was software-based, thus a computer crash could erase the data on an entire tape in 8 seconds. The
314:
when formatted on a ZX Microdrive (exact capacity depended on the number of "bad" sectors found and the precise speed of the
Microdrive motor when formatting). The data retrieval rate was 15 KB/s, i.e.,
298:
Microdrives used tiny (44 mm × 34 mm × 8 mm (1.73 in × 1.34 in × 0.31 in) including protective cover) cartridges containing a 5-metre (200 in)
250:
The
Microdrive was comparatively cheap (£49.95 at launch) and technologically innovative but also rather limited. Connecting a ZX Microdrive to a ZX Spectrum required the
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203:
It is claimed the
Microdrive concept was originally suggested by Andrew Grillet at an interview with Sinclair Research in 1974. Grillet proposed
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478:
910:
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86:
323:
258:
was launched for £99.95. This consisted of
Interface 1, a Microdrive, a blank cartridge and several cartridges containing
58:
471:
310:(30 in/s); thus performing a complete circuit in approximately 8 seconds. The cartridges held a minimum of 85
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unit, costing £49.95, although this could be bought packaged with a
Microdrive for £79.95. Later, in March 1985, the
105:
65:
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72:
43:
39:
222:, and never worked for Sinclair Research. Development of the ZX Microdrive hardware by Sinclair engineers
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system, modified to allow two 64k core images per track for roll-out roll-in swapping using the
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for greater reliability, and used a format incompatible with both ZX and QL Microdrives.
330:
cartridges were relatively expensive (initially sold for £4.95 each, later reduced to £1.99).
886:
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353:
In addition to the QL versions, dual internal
Microdrives were included in the related ICL
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A total of eight ZX Microdrive units could be connected to the
Interface 1 by
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Microdrives used tiny cartridges containing a 5-metre (200 in)
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and performed a complete circuit in approximately eight seconds.
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Microdrives were also used as the native storage medium of the
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one drive to the next via an electrical connector block.
306:, 1.9 mm (0.075 in) wide, driven at 76 cm/
155:, but it suffered from poor reliability and lower speed.
147:. It was proposed as a faster-loading alternative to the
493:
173:
The
Microdrive technology was later also used in the
365:Computerphone). These drives were re-engineered by
46:. Unsourced material may be challenged and removed.
342:The Sinclair QL featured dual internal Microdrives
410:"Infinite loop: the Sinclair ZX Microdrive story"
1473:
918:
479:
934:Sinclair computers, derivatives, and clones
218:Grillet was offered a better-paying job at
925:
911:
486:
472:
106:Learn how and when to remove this message
337:
237:
194:
119:
1497:Computer-related introductions in 1983
1474:
290:games, and an introductory cartridge.
906:
467:
407:
403:
401:
399:
242:Opened microdrive cartridge, with a
44:adding citations to reliable sources
15:
13:
396:
166:, which held a minimum of 85
14:
1508:
443:
991:
136:system launched in July 1983 by
20:
31:needs additional citations for
686:"Eighth" (0.15) inch (3.81 mm)
427:
199:Microdrive cartridge with case
190:
1:
699:KC standard, Compact Cassette
408:Smith, Tony (13 March 2013).
389:
333:
293:
256:ZX Spectrum Expansion System
7:
372:
357:system (also badged as the
233:
10:
1513:
989:
785:Three quarter inch (19 mm)
711:Tarbell Cassette Interface
495:Magnetic-tape data storage
459:, April 1985, News section
134:magnetic-tape data storage
1487:Home computer peripherals
1435:
1371:
1339:
1305:
1132:
1101:
1083:
1044:
1023:
1000:
940:
880:Four millimeter (3.81 mm)
879:
844:
809:
784:
777:
738:
685:
656:
627:
544:
509:
502:
450:ZX Microdrive information
1482:Computer storage devices
434:"Microdrive — 1983"
845:Eight millimeter (8 mm)
628:Eight millimeter (8 mm)
746:Exatron Stringy Floppy
657:Quarter inch (6.35 mm)
343:
247:
226:, David Southward and
200:
125:
739:Stringy (1.58–1.9 mm)
341:
241:
198:
123:
1219:ZX Spectrum based:
945:Science of Cambridge
40:improve this article
1427:Magnum Light Phaser
1392:Rotronics Wafadrive
1379:Beta Disk Interface
943:Sinclair Research /
810:Half inch (12.7 mm)
764:Rotronics Wafadrive
717:Commodore Datasette
545:Half inch (12.7 mm)
384:Rotronics Wafadrive
151:and cheaper than a
1363:FDD3000 Disk Drive
1349:Neptun 156 Monitor
1119:ZX Spectrum clones
1085:Cambridge Computer
452:at Planet Sinclair
436:, Planet Sinclair.
344:
248:
205:"a version of the
201:
185:personal computers
126:
124:ZX Microdrive unit
1492:Sinclair Research
1469:
1468:
1456:Richard Altwasser
1422:Stack Light Rifle
1417:RAM Music Machine
1372:Other peripherals
1340:Timex peripherals
1307:Sinclair Research
1046:Timex Corporation
1036:ZX Spectrum Vega+
900:
899:
896:
895:
773:
772:
510:Wide (19–25.4 mm)
363:Telecom Australia
230:started in 1982.
138:Sinclair Research
116:
115:
108:
90:
1504:
1273:ZX Spectrum Next
1229:CZ Spectrum Plus
1031:ZX Spectrum Vega
1024:Licenced systems
995:
927:
920:
913:
904:
903:
782:
781:
564:TX-2 Tape System
507:
506:
488:
481:
474:
465:
464:
437:
431:
425:
424:
422:
420:
405:
348:Sinclair QL
217:
111:
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89:
48:
24:
16:
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1507:
1506:
1505:
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1501:
1472:
1471:
1470:
1465:
1431:
1367:
1335:
1301:
1245:Scorpion ZS-256
1137:
1136:related systems
1135:
1128:
1107:
1097:
1079:
1040:
1019:
996:
987:
977:ZX Spectrum 128
947:
944:
936:
931:
901:
892:
875:
840:
805:
769:
734:
729:IBM PC Cassette
681:
652:
623:
540:
498:
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446:
441:
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428:
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416:
406:
397:
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375:
336:
296:
236:
204:
193:
112:
101:
95:
92:
55:"ZX Microdrive"
49:
47:
37:
25:
12:
11:
5:
1510:
1500:
1499:
1494:
1489:
1484:
1467:
1466:
1464:
1463:
1458:
1453:
1451:Rick Dickinson
1448:
1447:John Pemberton
1445:
1443:Clive Sinclair
1439:
1437:
1433:
1432:
1430:
1429:
1424:
1419:
1414:
1409:
1404:
1399:
1394:
1389:
1386:
1381:
1375:
1373:
1369:
1368:
1366:
1365:
1360:
1358:FDD Disk Drive
1355:
1350:
1347:
1346:TS2040 Printer
1343:
1341:
1337:
1336:
1334:
1333:
1328:
1326:ZX Interface 2
1323:
1321:ZX Interface 1
1318:
1312:
1310:
1303:
1302:
1300:
1299:
1289:
1275:
1217:
1155:
1140:
1138:
1133:
1130:
1129:
1127:
1126:
1121:
1116:
1114:ZX80/81 clones
1110:
1108:
1102:
1099:
1098:
1096:
1095:
1089:
1087:
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1080:
1078:
1077:
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1042:
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1039:
1038:
1033:
1027:
1025:
1021:
1020:
1018:
1017:
1015:ZX Spectrum +3
1012:
1010:ZX Spectrum +2
1006:
1004:
998:
997:
990:
988:
986:
985:
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961:
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453:
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444:External links
442:
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394:
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391:
388:
387:
386:
381:
379:Stringy floppy
374:
371:
335:
332:
324:daisy chaining
295:
292:
282:Games Designer
266:word processor
252:ZX Interface 1
246:for comparison
235:
232:
192:
189:
114:
113:
28:
26:
19:
9:
6:
4:
3:
2:
1509:
1498:
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1462:
1461:Steve Vickers
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1332:
1331:ZX Microdrive
1329:
1327:
1324:
1322:
1319:
1317:
1314:
1313:
1311:
1308:
1304:
1298:
1294:
1290:
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1274:
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1266:
1262:
1258:
1257:Komputer 2086
1254:
1250:
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1234:
1230:
1226:
1222:
1218:
1216:
1212:
1208:
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1200:
1196:
1192:
1188:
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1176:
1172:
1168:
1164:
1160:
1157:ZX81 based:
1156:
1154:
1150:
1146:
1142:
1141:
1139:
1134:Compatible or
1131:
1125:
1122:
1120:
1117:
1115:
1112:
1111:
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1100:
1094:
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1007:
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994:
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967:
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871:
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815:
814:
812:
808:
801:
797:
794:
790:
789:
787:
783:
780:
776:
765:
762:
759:
758:QL Microdrive
756:
753:
752:ZX Microdrive
750:
747:
744:
743:
741:
737:
730:
727:
724:
721:
718:
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712:
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514:
512:
508:
505:
501:
496:
489:
484:
482:
477:
475:
470:
469:
466:
460:
458:
457:Sinclair User
454:
451:
448:
447:
435:
430:
415:
411:
404:
402:
400:
395:
385:
382:
380:
377:
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370:
368:
364:
360:
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351:
349:
340:
331:
327:
325:
320:
318:
313:
309:
305:
304:magnetic tape
301:
291:
289:
288:
283:
279:
275:
271:
267:
263:
262:
257:
253:
245:
244:cassette tape
240:
231:
229:
225:
221:
215:
211:
208:
197:
188:
186:
183:
180:
176:
171:
169:
165:
164:magnetic tape
161:
156:
154:
150:
146:
145:home computer
143:
139:
135:
131:
130:ZX Microdrive
122:
118:
110:
107:
99:
96:December 2012
88:
85:
81:
78:
74:
71:
67:
64:
60:
57: –
56:
52:
51:Find sources:
45:
41:
35:
34:
29:This article
27:
23:
18:
17:
1353:TS2050 Modem
1330:
1283:One Per Desk
1191:CZ 1500 Plus
1187:CZ 1000 Plus
1143:ZX80 based:
973:ZX Spectrum+
823:Redwood SD-3
751:
456:
429:
417:. Retrieved
414:The Register
413:
359:Merlin Tonto
355:One Per Desk
352:
345:
328:
321:
300:endless loop
297:
285:
281:
269:
259:
255:
249:
224:Jim Westwood
202:
182:One Per Desk
172:
160:endless loop
157:
129:
127:
117:
102:
93:
83:
76:
69:
62:
50:
38:Please help
33:verification
30:
1309:peripherals
1297:Jupiter Ace
1203:Ringo R-470
1195:CZ Spectrum
1167:Lambda 8300
969:ZX Spectrum
641:IBM 3570 MP
606:LTO Ultrium
558:IBM 7-track
261:Tasword Two
191:Development
175:Sinclair QL
153:floppy disk
142:ZX Spectrum
1476:Categories
1316:ZX Printer
1277:QL based:
723:DECtape II
390:References
334:Later uses
294:Technology
287:Ant Attack
278:Quicksilva
270:Masterfile
228:Ben Cheese
216:protocol".
66:newspapers
1397:Multiface
1293:SAM Coupé
1237:Dubna 48K
1159:Apply 300
1124:QL clones
1103:Lists of
1066:(TC 2068)
315:120
1412:SpecDrum
1402:Kempston
1384:DISCiPLE
1279:CST Thor
1253:Kay 1024
1249:Sprinter
1233:Didaktik
1225:Pentagon
1199:NE-Z8000
1145:MicroAce
1064:T/S 2068
1059:T/S 1500
1054:T/S 1000
612:IBM 3592
588:IBM 3590
576:IBM 3480
552:UNISERVO
523:LINCtape
517:IBM 7340
373:See also
274:database
234:Products
210:Stereo 8
149:cassette
140:for its
1291:Other:
1287:Q40/Q60
1183:CZ 1500
1179:CZ 1000
1175:CZ 2000
1163:AS-1000
1075:TC 3256
1070:TC 2048
1002:Amstrad
887:DDS/DAT
858:Mammoth
778:Helical
570:9-track
535:CDC 626
529:DECtape
497:formats
419:11 July
207:Learjet
80:scholar
1436:People
1407:Currah
1241:Hobbit
1171:CP-200
1153:NE-Z80
1105:clones
889:(1989)
872:(1999)
866:(1996)
860:(1994)
854:(1987)
837:(2003)
831:(19xx)
825:(1995)
819:(1992)
802:(1992)
798:Ampex
795:(19xx)
766:(1984)
760:(1984)
754:(1983)
748:(1979)
731:(1981)
725:(1979)
719:(1977)
713:(1976)
707:(1976)
701:(1975)
695:(1971)
678:(1992)
672:(1986)
666:(1972)
649:(1999)
643:(1997)
637:(1995)
635:Travan
620:(2006)
618:T10000
614:(2003)
608:(2000)
602:(2000)
596:(1998)
590:(1995)
584:(1984)
578:(1984)
572:(1964)
566:(1958)
560:(1952)
554:(1951)
537:(1966)
531:(1963)
525:(1962)
519:(1961)
503:Linear
317:kbit/s
82:
75:
68:
61:
53:
1269:Robik
1261:TK90X
1207:TK82C
852:Data8
817:ArVid
791:Sony
705:DC100
693:D/CAS
676:Ditto
600:T9940
594:T9840
220:Xerox
132:is a
87:JSTOR
73:books
1388:MB02
1265:TK95
1215:TK85
1211:TK83
1149:TK80
964:ZX81
959:ZX80
954:MK14
835:SAIT
421:2018
361:and
284:and
214:KUTS
177:and
128:The
59:news
1221:ATM
1093:Z88
870:VXA
864:AIT
829:DTF
800:DST
793:DIR
670:SLR
664:QIC
647:ADR
582:DLT
367:ICL
302:of
280:'s
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272:(a
268:),
264:(a
179:ICL
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42:by
1478::
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1285:,
1281:,
1271:,
1267:,
1263:,
1259:,
1255:,
1251:,
1247:,
1239:,
1235:,
1231:,
1227:,
1223:,
1213:,
1209:,
1205:,
1201:,
1197:,
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1189:,
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1177:,
1173:,
1169:,
1165:,
1161:,
1151:,
1147:,
983:QL
975:,
412:.
398:^
312:KB
187:.
168:KB
1243:,
979:)
971:(
926:e
919:t
912:v
487:e
480:t
473:v
423:.
308:s
109:)
103:(
98:)
94:(
84:·
77:·
70:·
63:·
36:.
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