DISK INTERFACE Manual Supplement for version 4 of TR-DOS
Contents
1. The auto check may not work with some old 40 track disk drives because they do not have end stop However the 40 conmand may be used to inform the system that it is actually a 40 track drive The auto tests are carried out when power is applied to the Spectrum computer but to do this the disk drives must be switched on The tests will be carried out even if there is no disk in the drive If the disk drives are switches o f f then the test will be carried out when that particular drive is selected 3 40 COMMAND The tuto check may not wort with soma old 40 track disk drives because they do not have end stop That is the system thinks it is a 80 track drive The 40 command infornes the system that the currently selected drive is actually a 40 track drive Please note that the FORMAT command ignores the 40 command Therefore to format a diak on this kind of drive you must use the FORMAT utility program which is on the disk supplied 4 CAT COMMAND 4 1 The CAT commaand has been extended so that the listing of files can be dumped to a channel TR DOS v3 displays the catalogue on the screen In TR DOS V4 it can also be sent to a channel For example CAT 4 sends the listing of a catalogue to channel 4 CAT 6 B sends the listing of a catalogue of drive B to channel 6 4 2 The CAT command In the utility disk FILER program displays extended Information An example of the Information displayed by the FILER CAT command i2. there were files stored in track 1 to 12 on the disk they will be overwritten This file may be renamed using the NEW command or it may be copied to another disk The onmmand GO TO is used to load and run the image file During the loading of the file you will see some random display on the screen And when the loading has been completed the computer will continue to run the program from where it was stopped To load and run the saved image type GO TO filename COOE lt ENTER gt Note some games programs use a non standard key scan routine If a program does not work after loading from the disk you must change the name of the file to begin with a For example NEW test CODE lt ENTER gt Then you can run the program by typing GO TO test CODE lt ENTER gt 11 ADDITIONAL INFORMATION The disk system requires a buffer of 256 bytes one sector the printer buffer of the Spectrum computer is used However before the printer buffer is used it is saved in a free sector on the system track track 0 of the disk When the operation has been completed the printer buffer is re loaded fron the disk if the disk is write protected the printer buffer will be lost
3. DISK INTERFACE Manual Supplement for version 4 of TR DOS Technology Research Limited USER MANUAL FOR DISK INTERFACE Technology Research Ltd Unit 18 Central Trading Estate Staines Middlesex TW18 4XE England Copyright 1984 Typed and cleaned by Moffa Roger TECHNOLOGY RESEARCH BETA DISK INTERFACE TR DOS v4 TR DOS v4 for the Technology Research Beta Disk Interface Includes extra facilities and extends or modifies some of the original comands The password is no longer implemented The extra facilities are auto boot auto check of drive specification and file handling both sequential and random access In addition at the press of a button the whole image of the RAM may be saved on the disk The image may be retrieved from the disk to the RAM with the program continuing to run from where it was stopped A reset button is also provided Tha FORMAT and the COPY commands are now in the operating system in addition to the utility programs on the disk The utility program on the disk is now called FILER which combines the facilities of BACKUP COPY and SCOPY in TR DOS v3 The CAT comand has been extended while the LOAD and SAVE comands havebean modified This supplement explains these enhancements and should be used in conjunction with the user manual Contents 1 AUTO BOOT AUTO CHECK OF DRIVE SPECIFICATION 40 COMMAND CAT COMMAND LOAD COMMAND SAVE COMMAND COPY COMMAND FORMAT COMMAND 9 DISK ERROR 10 SEQUEN
4. FILER ver 4 0 1984 Technology Research Ltd Commands are CAT List of file name NEW newfile oldfile Rename ERASE filename Erase a file MOVE Remove empty gaps RETURN Return to System FORMAT name Format new disk COPY new old Copy file COPY b a Copy all files COPY s file Single drive copy COPY b Backup whole disk A The FILER CAT facility is fully covered in section 4 2 Single drive copy SCOPY is replaced by the COPY s command and the BACKUP is replaced by the COPY b command 12 RAM IMAGE SAVER AND LOADER When the button on the back of the interface is pressed the whole image of the computer s memory 48 kbytes will be stored on the disk so that the program which is running may be continued on a later day The following sequence show you the detailed operations Format a single sided disk see FORMAT command section 8 Insert the disk in drive A if it is not already there Return to BASIC Reset the Spectrum by typing PRINT USR 0 lt ENTER gt Load and run the program from cassette tape as normal Oa R wW rM After the program has loaded and is running press the button on the back of the Interface and release the button promptly The RAM image will then be saved on the disk Note that the disk must be formatted as single sided and it must be in drive A The name of this file is and the type is CODE The file is stored in track 1 to 12 If
5. TIAL AND RANDOM ACCESS FILE HANDLING 11 UTILITY PROGRAMS TAPECOPY amp FILER 12 RAM IMAGE SAVER AND LOADER 13 ADDITIONAL INFORMATION ON DOO FF W PDP TECHNOLOGY RESEARCH BETA DISK INTERFACE TR DOS v4 1 AUTO BOOT When the Spectrum is turned on or reset then TR DOS v4 will try to load and run a Basic program named boot If there is no disk in Drive A or the drive door is open or the disk does not contain the Basic program boot then an error message is displayed followed by the conmand line RUN boot You can run the boot program by pressing the ENTER key or yoo can delete the line and enter another command as required Having a disk in the disk drive when the Spectrum power is turned on may corrupt the disk particularly those makes of drive with permanently loaded heads It is therefore reconmended that the boot disk be loaded after the error message or the message be deleted as in the previous paragraph You can run or load the boot program by the following conmands RUN lt ENTER gt LOAD gt ENTER gt 2 AUTO CHECK DRIVE SPECIFICATION TR DOS v3 catered for disk drives with slow step rate and fixed the step rate accordingly TR DOS v4 checks the step rate of disk drives and adjust the rate automatically Thus modern drives with fast step rate are fully utilised In addition TR DOS v4 automatically checks the drive specifica ion that i s 40 or 80 track single or double sided and adjus Itself accordingly
6. ble A 11 UTILITY PROGRAMS TAPECOPY amp FILER There are three utility program to the disk suppliod The FORMAT program is the same as TR DOS v3 The TAPECOPY progcam allows you to transfer programs from cassette to disk And the FILER program replaces three utility programs in TR DOS v3 namely BACKUP COPY and SOOPY 11 1 TAPECOPY In many cases you may want to transfer programs from cassette to disk This program allows you to copy most programs onto disk It can copy BASIC CODE ARRAY and DATA file stored on tape providing that the length of the program is not greater than 40 000 bytes To enecute this program type RUN tapecopy lt ENTER gt You will get the following display TAPE TO DISK COPIER VER 4 0 TECHNOLOGY RESEARCH LTD DATA TYPE FILENAME CODE LENGTH START LINE BASIC LENGTH PRESS BREAK TO STOP START TAPE The program will wait for you to play the tape Once the tape HEADER is read the display w i show the data type filename code length start line and basic length For example if a BASIC called example with auto run line number 1000 and length of 15000 bytes is loaded then the display will be shown as TAPE TO DISK COPIER VER 4 0 TECHNOLOGY RESEARCH LTD DATA TYPE BASIC FILENAME EXAMPLE CODE LENGTH 15000 START LINE 01000 BASIC LENGTH 15000 PRESS BREAK TO 5TOP STOP TAPE When a file has loaded the display will inform you to stop the tape the program is th
7. ctor from the starting address And when the file is loaded all 256 bytes are loaded into the memory In TR DOS v4 this has been corrected so that the exact number of bytes are saved and loaded In order to implement this change the execution address has to be removed from the directory Therefore to auto run a machina code file the executing address must be the same as the starting address If this is not so than the RANDOMISE USR command can be used in BASIC For example SAVE TEST CODE starting_address length When the program is run it starts from the starting_address For example RUN TEST CODE NOTE Irrespective of the actual number of bytes saved the CAT command will show a sector Thus 310 by tes saved will show and use 2 sectors of the disk 7 COPY COMMAND The COPY command is now implemented in the TR DOS system instead of on the disk This command is usedd to copy files from one disk drive to another The format is COPY destination file source file type For example COPY B test A pie COPY A new B old CODE COPY B new A old DATA If you are copying all the files from diak drive A source to disk drive B destination then type COPY Be A If there is a file with the save name already existing on the destination disk drive then the system will prompt you with the following options overwrite existing file Y N The file will be overwritten if you answer Y If y
8. en stored on the disk with the same name as that stored on the tape If a file with the same name has already existed on the disk then it will be overwritten This process will repeat itself until you press the lt BREAX gt key The TAPECOPY program has its limitations they are 1 a A O N It cannot transfer protected programs Programs must not be longer than 40 000 bytes The messages which my be encountered are It can only transfer programs stored in standard format i e with header information It cannot transfer programs which are not in standard format e g headless recordings Programs transferred to disk may still have to be modified to enable the user to use the disk facilities refer to sections E amp F page 19 20 in the User Manual START TAPE Press the play key on the cassette recorder to start loading STOP TAPE Stop the casette recorder TAPE LOAD ERROR Errors encountered in loading rewind tape and try again NOT ENOUGH MEMORY This message tells you that you are trying to transfer programs greater than 40000 bytes long If so you can still transfer program by noting down the header information displayed 11 2 FILER The FILLR program replaces BACKUP COPY and SCOPY utility programs in TR DOS v3 In adition the CAT and the COPY commands have also been enhanced To execute this program type RUN filer lt ENTER gt The display in the screen will be
9. n a file for random access the command format is OPEN channel_number filename RND record_length For example OPEN 12 test01 RND 20 In this exaeple channel 12 is open for the random access file test1 with a record length of 20 characters Themaximum record length is 255 bytes The record is stored as a single string If the string is less than the record length it is stored left justified and is terminated by a carriage return ASCII code 13 the remaining bytes are not defined If the string is longer than the record length then it will be truncated to be the same as the record length and stored without the carriage return terminator A record may contain more than one variable However it is the responsibility of the program to link together the strings of those variables into a single string for the write operation The string must be split up during the read operation To write a record to a file the command format is PRINT channel_number record number variable_name For example PRINT 4 20 A The content of A is put in record number 20 21st record The first record number is 0 The contents will be lost if the power is turned off before the file is closed A file is closed by closing the channel To read the record from a file the command forma is INPUT channel_number record_number variable_name For example INPUT 4 15 A The record in record number 15 16th record is read and loaded to varia
10. ou want to duplicate or copy files from one disk to another disk using a single disk drive then the FILER utility program should be used 8 FORMAT COMMAND The FORMAT command is now implemented in the TR DOS system in addition to the utility on the disk This command is used to prepare a blank new disk for storing files The command automatically checks the drive specification and will format the disk accordingly The different type of disk are as follows 40 track single sided 40 track double sided 80 track single sided 80 track double sided For example FORMAT mydisk When the formatting has been completed the following is shown mydisk 624 624 where the first line is the name of the disk and the first number is the number of free sectors on the disk the second is the maximum number of sectors A track contains 16 sectors and there are 256 bytes in one qector Track 0 is reserved for system use Therefore there are 39 16 624 tracks and 624 256 159744 bytes 156 Ko in a 40 tracks single sided drive It is possible to force a double sided disk drive to format a disk as single sided by making the first character of the disk name a This is essential for use with the RAM SAVER see section 12 for example FORMAT mydisk 9 DISK ERROR If a disk error occurs TR DOS v4 will display an error message such as write protected or disk error followed by the track sector number where the error has occ
11. s as follows Title mydisk Disk Drive B 3 File s 40 Track s side 1 del file s Free Sector 580 File name Start Length line filer lt C gt 32 32768 08000 test lt B gt 5 00298 01200 100 phone lt gt 7 01780 01780 The display informs you that the name of the disk in drive B is mydisk It is 40 track single sided with 3 files stored and 1 file deleted There are 580 free sectors remaining on the disk The 3 files are filer test and phone filer is a machine code program occupying 32 sectors The starting and executing addresses are 32768 and the length of the program is 8000 bytes The basic program test will be auto run at line 100 while phone is a data file Sequential or random access 5 LOAD COMMAND The LOAD command has been changed If a Basic program is saved with a line number then when the file is loaded from the disk it will auto run at that line number If a Basic prograa is saved without a line number then the program will be listed when the file is loaded from the disk During loading and saving of files the lt BREAK gt key may be used to abort the command The commands will be also aborted if there is no disk in the drive and no disk will be displayed on the screen 6 SAVE COMMAND The SAVE command has also been changed When a machine code file is saved in TR DOS v3 it is saved as sectors That is if 10 bytes are to be saved the system actually saves the whole 256 bytes one se
12. sed renamed or copied as files of other types For example ERASE namadd NEW newfile oldfile COPY B phone A phone 10 2 Sequential Files A sequential file may be opened either for write or read but not both at the same time To open a file for write the command format is OPEN channel_number filename W When a channel is opened for write the basic PRINT command can be used to write data to this channel For example 10 LET DOS 15363 20 RANDOMISE USR DOS REM OPEN 4 test W 30 PRINT 4 This is a test line 40 RANDOMISE USR DOS REM CLOSE 4 The string in line 30 will be saved in file test on the disk When a write file is opened the contents will be lost if the power is turned off before the file is closed The file is closed by closing the channel as in line 40 Any file wich is closed may be reopened for a further write operation by reading adding and re saving under a new name or after erasing the first name To open a file for read the command format is OPEN 4 filename R When a channel is opened for read the basic INPUT command can be used to read data from this channel For example 10 LET DOS 15363 20 RANDOMISE USR DOS REM OPEN 7 test R 30 INPUT 7 A 40 CLOSE 7 The data file test will be loaded to A from the disk 10 3 Random access files All OPEN and CLOSE ccmmands require the usual RANDOMISE USR 15363 REM prefix but not the PRINT or INPUT commands To ope
13. ured There are 3 options available you can type R to re try A to abort the operation or I to ignore that track and sector and continue with the rest of the disk operations 10 SEQUENTIAL AND RANDOM ACCESS FILE HANDLING 10 1 General description Normal datafiles e g SAVE LOAD name a produced by many programs are still handled as in TR DOS v3 The CAT command identifies these as type lt D gt There are now two additional types of datafiles sequential and random access In order to use these datafiles you must first open a channel The Spectrum contains 16 channels Channels 0 to 3 are reserved for the computer You can use channels 4 to 15 When a disk channel is open for file handling 336 bytes of RAM are used When the CAT command is used to list the catalogue these datafiles are distinguished from other types by lt gt For example TEST lt gt Both numeric and string variables may be stored in the datafiles Numeric variables are converted into strings by the computer before being put into data file The string is terminated by a carriage return ASCII code 13 The sequential file stores the data serially In order to read a string towards the end of these files it is necessary to start from thee very beginning The random access file stores data as a number of records Any record in these files may be read or written by specifying the record number The sequential and random access files may be era
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