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2.  Handling  magnetic  discs. 

The following are  a  few do's  and  don'ts  which  apply when  handling  5.25 
inch  floppy  or  3  inch  microdiscs. 

Do  not  touch  any part  of the  disc  magnetic  surface  which  is exposed  by 
the  gap  in  its  protective  cover. 

(5.25 

inch  flexible  discs  only). 

Keep  the  disc  from  being  exposed  to  magnetic  fields  at  all  times. 
Exposure  to  a  magnetic  field  for  an  instant  will  corrupt  the  data  on  the 
disc. 

Store  the  data  in  a  dust  free  area  with  a  temperature  not  greater  than 
50°C  and  away  from  bright  sunlight. 

Do  not  clean  a  disc with  anything other  than  an  approved  agent  (consult 
your  dealer). 

Do  not  bend  or  deform  a  disc.  (5.25  inch  flexible discs  only). 

Try  to  write  on  the  label  before  you  stick  it  to  the  disc  jacket,  writing 
could  damage  the  magnetic  surface.  (5.25  inch  flexible  discs  only). 

Do  not  open  the  disc  drive  front  shutter  whilst  a  function  is  being 
executed  (when  the  red/green  light  on  the  front  of  the  drive  unit  is 
illuminated. 

3.  Protecting  data  on  the  discs. 

You  will  find  that  there  are  certain  instructions  used  for  writing  data 
onto  discs  such  as  C O P Y ,   B A C K U P   and  SAVE.  T h e r e   is  also  the 
D E L E T E   instruction  for  completely  removing  whole  files  of  data. 
These  instruction  make  it  very easy  to  destroy  large  chunks  of data  and 
if  it  is  important  data  not  recorded  elsewhere  the  results  can  be 
catastrophic!  As  explained  previously,  every disc  (micro or  flexible) has 
a  'write  protection'  device,  however  there  is  another  way  you  can 
protect  against  loss  of  data  (especially  damaged  discs)  and  that  is  t0 
keep  copies  of  all  working  discs,  these  copies  are  commonly  known  as 
'backups'  and  if  'backups'  are  tO  be  useful  they  need  to  be  regularly 
updated  depending  on  how  often  you  change  the  information  on  your 

working  discs. 

20 

Summary of Contents for MICRODISC

Page 1: ......

Page 2: ...THE ORIC MICRODISC MANUAL...

Page 3: ...re may be errors or omissions Oric can accept no responsibility for such omissions and or errors nor for damage or loss resulting from work carried out on the product by persons other than those autho...

Page 4: ...supply unit which plugs directly into the mains electricity supply If you suspect this unit of being faulty DO NOT attempt to remove the outer case and plug the unit into the mains with the inside exp...

Page 5: ...s Connecting up and switching on Making a Backup Copy of the system disc USING THE MICRODISC FUNCTIONS General Instructions HELP Pages BACKUP a complete disc COPY file s DELETE a file or set of files...

Page 6: ...ENDIX ILLUSTRATIONS Magnetic disc surface 40 tracks 10 sectors A 3 inch microdisc and a 5 25 inch flexible disc A system with four disc drive units ORIC microdisc drive unit showing disc insertion Err...

Page 7: ...actly how data is organized on a magnetic disc surface Chapter 3 deals specifically with the ORIC microdisc system telling you exactly what you get what the system is capable of and briefly how it wor...

Page 8: ...switched on or off For this reason your computer is designed so that it can be connected to a storage device which enables you to permanently store anything that is in computer RAM and even more usef...

Page 9: ...storage capacity for example a disc having a capacity of 256k bytes can store 256 000 characters The two disc types which can be used on the ORIC system are very different to look at The 5 25 inch fle...

Page 10: ...Sector 256 bytes long 10 K 9 J 2 B 8 H 3 c 7 G 6 F Track 39 Track 0 Figure 1 Magnetic disc surface 40 tracks 10 sectors 1 A 4 D 5 E...

Page 11: ...ich files are on a disc In addition to a list of filenames each directory when it holds the maximum of fifteen filenames also holds the sector location of the next directory Figure 2 shows both types...

Page 12: ...rtion direction Write protect hole for A side Write protect switch for A side Access slot for read write heads Write protect switch for B side Write protect hole for B side Mechanical drive hole A 3 i...

Page 13: ...e more sophisticated data handling features can be built into the disc than is possible for a tape cassette storage system which usually requires manual operation of the press button controls Because...

Page 14: ...can give instructions to the computer telling it how to use the microdisc drive s In addition to the DOS there is also a lot of information on the system disc in the form of help pages and we shall te...

Page 15: ...ectronic interface circuitry which enables it to be connected directly to and controlled directly from the microcomputer It also has a red reset button on the rear the purpose of which is explained in...

Page 16: ...25 DISCS POWER UNIT mains MONITOR OR TELEVISION MICROCOMPUTER SLAVE DISC DRIVE UNIT 2 3 OR 5 25 DISCS SLAVE DISC DRIVE UNIT 1 3 OR 5 25 DISCS mains MASTER DISC DRIVE 0 3 DISCS Figure 3 A system with...

Page 17: ...units you will need an extra power supply unit A 5 25 inch floppy disc drive can also be used as a slave however these are not sold by ORIC and you should refer to their manuals provided for user ins...

Page 18: ...it and store it away If you have just purchased a microcomputer there is no need to unpack the power unit Now refer to Page 11 of the ORIC 1 User Guide or Page 2 of the ATMOS Manual you will see that...

Page 19: ...supply and the television there is no on off switch on the disc drive unit There may or may not be a sensible message on the screen however this does not matter because the next thing to do is press t...

Page 20: ...slot Disc lock release bar switch Front view of drive with disc being inserted Reset button DIN power socket 34 way socket Rear view of drive Figure 4 ORIC Microdisc drive unit 15 Ribbon cable 34pinp...

Page 21: ...the disc without affecting the system in any way MAKING A BACKUP COPY OF THE SYSTEM DISC Now that you have loaded the DOS into computer memory it would be a good idea before doing anything else to ma...

Page 22: ...procedure starting with the typed instruction If you do not wish to format another disc type N or any other character and press When formatting has finished remove the disc Now you can make a backup c...

Page 23: ...ed on the keyboard and any restrictions or constraints regarding the use of the function Before you use the microdisc there are one or two important points you should be aware of regarding disc handli...

Page 24: ...out this means you must press a key not type a word For example RETURN means the RETURN key not the word return Where you are required to type in text characters and or numbers these are shown in bold...

Page 25: ...5 25 inch flexible discs only Do not open the disc drive front shutter whilst a function is being executed when the red green light on the front of the drive unit is illuminated 3 Protecting data on...

Page 26: ...art is called the name and the third part is called the extension The name part can be a maximum of any six alphanumeric characters in any order and the extension part can be a maximum of any three al...

Page 27: ...umber of letters and or digits in any combination and specifies any number or letter The only requirement is that you must specify no characters after the in the name part or the extension Below are s...

Page 28: ...er being written to is the target If you do not specify a drive number where the instruction requires one the system will allocate the default drive 8 Information messages From time to time messages a...

Page 29: ...ing you what is available in the help pages in addition there are also instruction telling you what to type in for displaying pages You will notice that the list contains the names of information item...

Page 30: ...ther way of selecting more than one item is to specify a character or characters common to the items you want For example if you type HELP D RETURN all information items whose names start with D will...

Page 31: ...s full no more data is read from the disc at this stage the message insert target disc is displayed 3 Now remove the system disc and insert your blank disc The data in the buffer is now written onto t...

Page 32: ...TO target drive number All the data will now be read from the source disc and written onto the target disc When backing up is completed a message to that effect will be displayed 3 Remember to remove...

Page 33: ...or a different one Copying either to the same disc or a different disc can be done using one or two disc drives The new file s can be given a write protected or unprotected status or can assume the st...

Page 34: ...nsert source disc and insert target disc will be displayed so that you know when to change discs 0 or M Overwrite or merge options Only one of these can be specified It is often necessary to create a...

Page 35: ...each time any of the old files is merged into the new file NOTES 1 When a new filename is created as a result of copying a message to that effect is displayed 2 If the new filename is the same as the...

Page 36: ...EXAMPLE INSTRUCTIONS The COPY function is extremely versatile and probably the best way of illustrating its many uses is to give you some examples of instructions 1 To copy the file FRED EXT on drive...

Page 37: ...on the same disc in the default drive with no change of write protection status COPY GEORGE TO PETER RETURN 6 Copy a file called GEORGE on the disc in drive 2 to a file called PETER on the same disc...

Page 38: ...ccupied by the deleted files is free to be used again INSTRUCTION DEL ambiguous filename Notes 1 If no disc drive number is specified in ambiguous filename the default drive is used 2 You cannot delet...

Page 39: ...ile Remember that you specify the drive number as part of the filename or ambiguous filename and that you can use wildcard characters to specify an ambiguous filename When you request a directory list...

Page 40: ...es There are two files per line and each has a number showing the number of sectors in that file P indicates a file is write protected In this case there are 5 files two of which are write protected I...

Page 41: ...ot If you do not specify the drive number the system automatically selects the default drive as defined by this function INSTRUCTION DRV drive number You do not have to enter a drive number in which c...

Page 42: ...to the drive and press RETURN Insert the blank disc in the drive unit and press RETURN Formatting will now take place and a message will tell you when the disc is formatted and will also ask if you wi...

Page 43: ...execution address this option will prevent it from being automatically run after loading has taken place A address When a program is saved the start and end addresses in memory from which it was saved...

Page 44: ...uous filename option Where option P to protect file N to remove protection from a file I to protect a file and remove its name from the DIRECTORY listing when displayed in other words the file becomes...

Page 45: ...file DESCRIPTION To change the name of a file held on disc INSTRUCTION RENAME Filename to Filename NOTES 1 Ambiguous filename cannot be used 2 The new filename must not be already in use on the disc 4...

Page 46: ...E define the start and end of memory to be saved and option T defines the address at which the program will be automatically run when loaded Save a block of memory not a program The instruction is as...

Page 47: ...atically run when it is loaded RETURN SAVE PROGM A B400 E C250 RETURN An area of machine code memory from address hexadecimal B400 to C250 is saved under the filename PROGM There is no transfer addres...

Page 48: ...The title and version number of the DOS on the disc A list of which keys to press in order to specify the various configuration details The currently specified configuration of drive 0 If you wish to...

Page 49: ...N a new file for writing you cannot PUT data in an existing file When writing is finished you must CLOSE the file Once a file is CLOSED created you can OPEN it for reading only GET data from it and CL...

Page 50: ...currently OPEN for reading from or writing to If the file was open for writing to a new file is created by CLOSE INSTRUCTION CLOSE option Where the options are W if the file is open for writing R if...

Page 51: ...es of bytes GET DATA from a file DESCRIPTION To read specified data from a file on disc and load it into RAM INSTRUCTION GET data NOTES 1 This instruction can only be used after an OPEN instruction ha...

Page 52: ...TORE array name excluding dimension filename NOTES 1 The array name can have any number of dimensions 2 The array must already be in memory in other words you cannot type in the instruction and then t...

Page 53: ...f DAT as is the case in STORE 2 The file must have previously been stored using STORE not SAVE instruction 3 An array name can have any number of dimensions i e you can allocate it any amount of memor...

Page 54: ...s a file that does not exist ERROR 2 invalid command end The command name was understood but the option was not ERROR 3 no drive number FORMAT requires a drive number ERROR 4 bad drive number The syst...

Page 55: ...not possible to use OPEN more than one file for reading or for writing ERROR 12 illegal quantity The number used is illegal ERROR 13 end address missing If a start address is specified in SAVE then a...

Page 56: ...is the one overwritten then the file may extend itself until disc space is exhausted ERROR 21 single target file illegal COPY ing a group of files and specifying a target file is illegal unless the m...

Page 57: ...t change the disc may give this error ERROR 27 incompatible drives This error is generated by BACKUP It is not possible to backup a double sided disc to a single sided drive for example ERROR 28 file...

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