Epson TF-20 User manual

FLEXIBLEDISKUNIT
HX-20DISKBASIC
REFERENCE
MANUAL

FOREWORD
Thismanualcoversthespecificationsanduseofthehardwareand
softwareoftheTF-20FlexibleDiskUnitdesignedexclusivelyforusewith
theHX-20portablecomputer.TogetthefullestusefromyourTF-20.
pleasereadthismanualcarefullybeforeattemptingtooperatetheunit.
NOTICE:
Allrightsreserved.Reproductionofanypartofthismanualinanyform
whatsoeverwithoutEPSON'Sexpresswrittenpermissionisforbidden.
*Thecontentsofthismanualaresubjecttochangewithoutnotice.
*Alleffortshavebeenmadetoensuretheaccuracyofthecontentsofthismanual.
However,shouldanyerrorsbedetected,EPSONwouldgreatlyappreciatebeing
informedofthem.
*Theabovenotwithstanding,EPSONcanassumenoresponsibilityforanyerrors
inthismanualortheirconsequences.
*MicrosoftBASICisa trademarkofMicrosoft.
©Copyright1983byEPSONCORPORATION
Nagano,Japan

TABLEOFCONTENTS
FOREWARD.............................................................................................................i
1.INTRODUCTION..........................................................................................1-1
1.1 Sequential Files and Random Access Files ................................................ 1-2
1.2FlexibleDisks..............................................................................................1-2
2. GETTING STARTED.................................................................................... 2-1
2.1Unpacking...................................................................................................2-1
2.2NamesofParts...........................................................................................2-2
2.3HardwareConfiguration.............................................................................2-2
2.4 Operation.................................................................................................... 2-4
3.DISKS.............................................:.............................................................3-1
3.1DiskFormat................................................................................................3-1
3.2SystemandNon-SystemDisks..................................................................3-2
3.3FRMAT.SYSGENandCOPY......................................................................3-3
3.4CautionswhenReplacingDisks.................................................................3-4
3.5CareandHandlingofFlexibleDisks............................................................3-6
3.6 Cautions on Placement of Disk Drive ......................................................... 3-9
4.DISKBASIC.................................................................................................4-1
4.1DiskBASICFeatures..................................................................................4-2
4.2BootingDiskBASIC....................................................................................4-3
4.3DiskBASICSyntax.....................................................................................4-5
4.4CommandsandStatements.......................................................................4-6
4.5DiskBASICFunctions.................................................................................4-31
4.6 COPY Utility................................................................................................ 4-36
4.7 Error Processing ......................................................................................... 4-39
5.HARDWARE................................................................................................5-1
5.1HardwareConfiguration.............................................................................5-1
5.2InterfaceSignals.........................................................................................5-2
5.3InterfaceLevel............................................................................................5-3
APPENDIXES
AERRORCODES
BDISKDRIVEENVIRONMENTALCONDITIONS
CPOWERREQUIREMENTSANDOUTLINEDIMENSIONS
DDISKSPECIFICATIONSANDENVIRONMENTALCONDITIONS

CommandsandStatements
Directions
CLOSE...................................4-6CVI,CVS,CVD..........
DSKO$...................................4-7DSKF........................
FIELD.....................................4-9 DSKI$.......................
FILES.....................................4-10EOF...........................
FILNUM.................................4-11INPUT$.....................
FRMAT..................................4-12LOC...........................
GET........................................4-13LOF...........................
INPUT#.................................4-14MKI$,MKS$,MKD$.
KILL.......................................4-15
LINEINPUT#........................4-15
LIST.......................................4-16
LOAD.....................................4-16
LOADM.................................4-17
MERGE..................................4-18
LSET,RSET...........................4-19
NAME....................................4-20
OPEN.....................................4-21
PRINT#.................................4-22
PRINT#USING.....................4-23
PUT........................................4-24
RESET...................................4-25
RUN.......................................4-26
SAVE.....................................4-27
SAVEM..................................4-28
WHILE...WEND.....................4-29
SYSGEN................................4-30
.4-31
.4-32
.4-32
.4-33
.4-33
.4-34
.4-34
.4-35
1.INTRODUCTION
1.1SequentialFilesandRandomAccessFiles
Thereareessentiallytwowaysinwhichdatacanbeaccessed(storedand
retrieved).Thesearesequentialandrandomaccessfiles.
Asthenamesuggests,sequentialfilesarefilesinwhichthedataare
storedinsequence.Therefore,toretrievedatafromthefile,thedatamust
bereadinsequenceandunwanteddatamustbepassedoveruntilthe
desireddataisreached.Amongtheadvantagesofsequentialfilesisthe
factthat,sincethedataarestoredinsequence,theonlyrestrictiononthe
lengthofa fileistheamountofmemoryavailableonthestoragemedium.
Thesimpleconfigurationofsequentialfilesalsomakesthemquiteeasyto
understandandtohandle.Themaindrawbackofsequentialfilesisthat
becauseunwanteddatamustbe.passed,theyarequiteslowcompared
withrandomaccessfiles.Thecassettetapesusedintheexternalcassette
andthemicrocassettedriveoftheHX-20arebothsequentialstorages.
Ina randomaccessfile,itispossibletogodirectlytothelocationinthe
storagemediumwhichyouwishtoreadorwrite.Thissavesa greatdealof
timeandmakesrandomaccessfilesfastertoaccessthansequentialfiles.
However,forrandomaccessfiles,inordertobeabletolocatedataeasily,
itisnecessarythatallrecords(thebasicunitforhandlingdatainfiles)be
thesamelength.
InDiskBASIC(thenameoftheversionofBASICusedtooperatethe
TF-20),thefixedlengthofrecordsis128bytes.Tofixthelengthofthe
variablesusedina randomaccessfile,theFIELDstatementisnecessary.
LSETandRSETstatementsareusedtostoredataintherandombuffer.
Theadvantageofrandomaccessfilesisthattheyareveryfastandthe
disadvantagesarethattheyusememorylessefficientlythansequential
filesandmustbeconfiguredwithsomecare.TheTF-20canbeusedfor
bothsequentialandrandomaccessstorage.
IV
1-1

1.2FlexibleDisks,
Flexibledisksarea lightweight,low-coststoragemedium.Whenthedisk
isinsertedinthediskdrive,itisrotatedata speedofthe300RPMbythe
spindleinthespindlehole.Accessisperformedthroughtheread/write
accessholesbytwinread/writeheadslocatedoneithersideofthediskin
thedrive.TheflexibledisksusedintheTF-20aredouble-sideddiskswhich
measure5 1/4"dia.andhaveanavailabletotalstoragecapacityof278K
bytes.Thefigurebelowshowstheexternalviewof thedisksusedinthe
TF-20.
Alongwiththeadvantagesofflexibledisks,therearecertainconditions
whichmustbemetconcerningtheiruse.Primarily,thesefallunderthe
headingofthecarewithwhichflexibledisksmustbetreated.Thedensity
withwhichdataismagneticallyrecordedona disk,whilebeingthesource
ofitsefficiencyandeconomy,isalsothereasonwhycaremustbe
exercisedinthehandlingof disks.Carelesshandlingof diskscanresultin
lostoruselessdataandprograms.
Disksarehoused' a protectivejacketthatservestocleantherecording
surfaceandprotectitfromdustandothercontaminants.Therecording
surfaceshouldneverbeexposedtooils(includingthatonyourfingers),
solventsora dustyatmosphere.Anyofthesecandestroythedataand
programsstoredonthedisk.Thesameappliestoextremetemperatures
orsuddenfluctuationsintemperatureorhumidity.Becausethedisks
recorddatamagnetically,disksshouldneverbeusedorstorednear
magnetsorina strongmagneticfield,suchasthatproducedbya
televisionset.Fordetailsoftherecordingformatandcompletewarnings
foruse,refertoChapter3,Disks.
1-2
1-3

2.GETTINGSTARTED
2.1Unpacking
WhenunpackingtheTF-20,makesurethatallofthefollowingitemsare
included.
®
Fig.2.1PackingList
AllpackingmaterialsshouldbesavedforreshipmentoftheTF-20.
2-1

2.2NamesofParts
2.3HardwareConfiguration
UptotwoTF-20floppydiskunits,eachhousingtwodrives,canbe
connectedtogetherina daisychainwiththeHX-20.InDiskBASIC,the
designationofthedrivesofthefirstunitaredrivesA andB andthoseinthe
secondunit,drivesC andD.Thedrivenamesaredeterminedbythe
settingoftheDIPswitcheslocatedinsidethehousingoftheTF-20.The
factorysettingisfordrivesA andB andtheusermustresettheDIP
switcheshimselfwhenheaddsa secondunit.Theprocedureforaddinga
secondTF-20isasfollows.
(1)Loosenthefourscrewslocatedontheloweredgeofthecoverofthe
secondTF-20.ChangethesettingofDIPswitch4 toOFF.DIPswitch4
islocatedontherear,lefthandsideofthePCboard(infrontofthe5-pin
interfaceconnector).ThelocationofDIPswitch4 isshownintheFig.
2.3.
2-2
TurnDIPswitch4OFF
Fig.2.3Right-sideViewofTF-20
WhenDIPswitch4 hasbeensettotheOFFposition,thediskdrivecan
beusedastheseconddrive.Thedevicenameswillbe"C:"and"D:".
(2)ConnecttheDIN5-pinendofcable#707tothe5-pinconnectorofthe
firstTF-20.
(3)ConnecttheDIN6-pinendofcable#707tothe6-pinconnectorofthe
secondTF-20."Daisychaining",asthisconnectioniscalled,ofthe
HX-20totwoTF-20drivesisshowninthefigurebelow.
TF-205-pinDIN
Fig.2.4DaisyChainingtheHX-20toTwoTF-20Units

2.4Operation
(1)DIPswitchsettingoftheHX-20
Beforestartingup,DIPswitch4 oftheHX-20mustbeturnedONIfitis
notturnedON,youwillnotbeabletobootDiskBASICeveniftheTF-20
unitsarecorrectlyconnectedtotheHX-20.
(2)TurningthepowerONandOFF
ThepoweroftheHX-20mustbeturnedONafterpowerhasbeenapplied
toalltheterminalsThepowerof theHX-20mustbeturnedOFFbefore
turningOFFthepowerofanyoftheterminals
RemoveanydiskssetintheTF-20beforeturningthepowerONorOFF.
(3)Settingdisksinthediskdrive
Theprocedureforsettingdisksinthediskdriveisasfollows
STEP1
Insertthediskintothediskdriveso thatthewriteprotectnotchisatthe
topofthediskandtheidentificationlabelisfacingright.
Fig.2.5SettingDisksintheDrive
STEP2
Whenthediskisinserted,youwillheara soundastheejectlocklever
catches
STEP3
PressthepushbuttonslowlyandcarefullytotheONposition.Thedisk
nowsetinthedrive
2-4
PushbuttonOFF'' PushbuttonON
Fig.2.7PushButton

(4)Removingdisksfromthediskdrive
Theprocedureforremovingdisksfromthediskdriveisasfollows.
STEP1
Checktomakesurethatthedriveselectindicatorisnotilluminatedbefore
pressingthepushbutton.Ifthedriveselectindicatorisilluminated,
executeCLOSEorRESETstatementbeforeyouejectthedisk.Thedrive
selectindicatorwillturnoffa fewsecondsaftertheexecutionofoneofthe
abovestatements.
Pushbuttons
selectindicators(LED)
Fig.2.8RemovingDisksfromtheDrive
STEP2
Firmlypressthepushbuttonofthediskdrivefromwhichyouwishtoeject
thedisk.ThepushbuttonwillreturntotheOFFpositionandthediskwill
beejected2-3cmfromthedrive.
CAUTIONS
1) Insert the disk into the drive slowly and carefully.
2) Check the orientation of the disk (write protect notch up, identification
label to the right) before setting the disk in the drive. (If the orientation
of the disk is not correct, the TF-20 will not operate.)
3) Always remove disks from the drive after checking to make sure that
the drive select indicator is extinguished. If you eject a disk while the
drive select indicator is illuminated, you risk losing the data stored on
your disk.
3. DISKS
3.1DiskFormat
TheflexibledisksusedintheTF-20aredouble-sided,double-density
flexibledisks.Double-sidedmeansthatdatamaybestoredonbothsides
(sides0 and1)of thedisksbymeansof theread/writeheadsoperating
throughtheaccessholes.Doubledensityreferstothedensitywithwhich
datacanbestoredonthedisks.
Therecordingsurfaceoftheflexiblediskisdividedinto40concentric
bands,calledtracks.Thesearereferredto,fromtheoutermosttothe
innermost,astracks0 to39.
Eachtrackisfurtherdividedinto16sectors.Thesearethebasicphysical
unitofdatastorageonthedisk.Atthestartof eachsectorisanareathat
showsthestartofthesectorandcontainstheaddressdataforthesector.
ThisisreferredtoastheidentificationorIDfield.TheIDfieldisfollowedby
thedatafield.Thisiswherethedatawhichtheuserwishestostoreis
actuallywritten.Theamountofdatathatcanbestoredina singlesectoris
256bytes,or4Kbytes(1Kbyte= 1,024bytes)pertrackfora totalcapacity
of320Kbytesfortheentiredisk.
2-6
3-1

Fig.3.1FlexibleDisk
Ofthistotal,tracks0 through3 (sides0 and1)areusedasthesystemarea
(fortheoperatingsystemoftheTF-20),thefirst8 sectorsoftrack4 (side0)
areusedasthedirectoryareaandtrack39isreserved.Thus,thefilearea
availablefortheuseris278Kbytes.Ifthediskisa systemdisk,theamount
willbereducedbythe8Kbytesoccupiedbythesystemprogram(which
operatesDiskBASICintheHX-20).
Foreachflexibledisk,64directoryareasarereserved.Thus,themaximum
numberoffilesthatcanbecreatedona singlediskis64However,a new
directoryareaisrequiredforevery256records(32Kbytes)ofa fileandthis
willhaveaneffectonthetotalnumberoffilesthatcanbecreated.
3.2SystemandNon-SystemDisks
ThediskswhichcanbeusedintheTF-20aredividedintosystemand
non-systemdisks.Thedifferencesbetweenthetwoareasfollows.
3-2
availableforusebytheuser.
3.3FORMAT,SYSGENandCOPY
Thesetwocommandsandoneutilityprogramareusedtoperform
necessaryoperationstoyourdisks:toformatthem,tocreatenewsystem
disksandtocreatebackupdisks.
(1)FRMAT
Beforea diskcanbeused,theaddressdatamustbewrittenintotheID
fieldandallotherdatanecessaryfordatastoragemustbepresentonthe
disk.Theprocessofwritingthisdatatothediskiscalledinitilization.Disks
suppliedbyEPSONarealreadyinitializedandcanbeusedimmediatelyas
non-systemdisks.However,disksotherthanthosesuppliedbyEPSONor
thoseonwhichdatahasbeendestroyedmustbeinitializedbytheuser.
ThisisdonebytheFRMATcommand.
Toformata disktobeusableintheTF-20,inputFRMATfollowedbythe
drivenameinwhichthediskyouwishtoformatisset.Whena diskis
formatted,allof thedataonthedisk(includingthesystemprogram)willbe
destroyed.Therefore,theHX-20asksforconfirmationbydisplayingthe
message"Areyousure?".Input"Y"fromthekeyboardifyouwishto
executethestatementand"N"ifyouwishtocancel.See4.4Commands
andStatementsfordetails.
3-3