¢ USING B-TAPE¢¢ The access to tape in high-speed mode is provided by device handler "B:". This handler uses filenames, so the full specification should be "B:name.ext". The syntax of a filename is the same as for disk-files under BW-DOS (including wildcards). You can select the "B:" device as working drive in the CP (by typing "B:"). The length of tape-files under BTAPE is limited to 257040 bytes.¢¢¢ Using the recorder under B-TAPE¢¢ B-TAPE routines are using simple sound signals for communication with the user during the I/O operations.¢ Recording a file on tape starts with the well known "double beep" sound (known also from "C:"). It's necessary to find the correct place on tape, press <PLAY> and <RECORD> on the recorder, and then <RETURN> on computer. BTAPE will then record a sound signal "start of file" (a short melody going up and down again) followed by the file itself.¢ Reading a file starts with a single "beep" (also known from "C:"). You needn't to press any keys on computer - the program waits for data immediately after the "beep", so just press <PLAY> on recorder. BTAPE will search for a file and check its name. When the name don't match the file-specification, a sound signal "bad file" appears (exchanging two tones) - it's of course necessary to move the tape to correct file. If you don't know where it is, abort the operation with <BREAK>, and use the "DIR" command for orientation. When no readable block is found for 4 minutes, the operation is terminated (Error 138).¢ The program may ask you also for moving the tape to the correct block in the file - mostly the first block. A simple melody that is going up indicates that you should use the <F.FWD> button (or wait - if the correct block is not too far), and a melody going down asks you to use the <REWIND> button.¢ While searching for the correct file and block, the program accepts any file that match the file-specification. But once a block with correct name and serial number is found, the program goes to reading mode. Then, no blocks from other files are accepted - even if the filename is identical.¢ The sound signals "F.FWD", "REWIND", and "bad file" may also occur during the reading process. One of the possible reasons is that reading of some block failed, and so the program asks you to rewind tape for retry. This may be also caused by bad length of the gaps between blocks (more info will come later). Another possible reason is a request from the application software to read from an other position in the file (the POINT function - it occurs for example with the command "OFFLOAD").¢ When the tape stops for a longer time (the reading is finished, or interrupted - for example some kind of intro is working while loading a game), it's good to press <STOP> on the recorder to avoid damage of the tape.¢¢ During the high-speed tape operations, the TV screen is off. While recording to tape, the screen is simply black, and while reading, it shows the signal from tape. Disabling the TV screen is necessary to allow exact timing of the I/O routines (no hardware support is available for the used format).¢ BTAPE installed under OS-ROM may also sometimes affect displaying of text modes (because of switching the ROM off for executing some of BTAPE routines). The problem is only on the screen; it may not cause any damage.¢¢ The first operation executed on a disk drive after a tape-oriented operation will allways begin with a short pause (1 sec). This is necessary to avoid crashing the first disk I/O by the tape recorder, that is unfortunately "active" also a while after turning off (because of its capacitors). This function is very important while copying files from tape to disk.¢ When the "XFSIO" command is used, it must be installed before BTAPE. Otherwise it may override the mentioned function (the pause).¢¢¢ Selecting mode and speed¢¢ While recording a file to tape, the parameters "mode" and "speed" are important.¢ The speed depends on the quality of used recorder and tape. Mostly you'll be able to use even the highest speeds, but when there was problems with the hardware-expansion, or you'll access the same tape with more recorders, it's good to select a lower speed. The default speed 12 should be OK in most cases.¢ The function of "double blocks" means that every block will be recorded twice. In this mode, the file may survive small drop-outs on the tape, but the effective speed of transmission is decreased of course. This mode is good especially for very important files. The first block of every file is allways doubled. This allows programs like "COPY" to find the file with the "DIR" function, and then start reading immediately, and it also helps in the case that recording overruns into next file on tape a little.¢ The length of gaps between blocks depends on the software, that will read the file later. In most cases, the mode of short gaps is good - this mode is for programs that read the whole file at once, without of pause. In this mode, the tape recorder don't stop between the blocks, and the reduced length of gaps is saving time. When the application software needs too long time for interpretation of the received data, the recorder will stop after a while automatically. While recording to tape, it is no problem (you'll only get a bit longer gap), but while reading from tape, the recorder will overrun the begin of next block. In this case you'll need to use the <REWIND> button - this indicates that the mode of long gaps would be better. In this mode, the recorder stops after each block, and the gaps are long enough for the recorder to stop/start while reading from tape. It decreases the transmission-speed of course, but the application software have now unlimited time to interpret the data. This mode is good for example while doing I/O operations using Basic-commands.¢ The binary program-files are a special case. Mostly the short gaps are OK, but there are programs (especially games and demos) that execute pretty long actions between loding - different intros, depacking etc. Because this occurs only on a few places in the (mostly quite long) file, the mode of long gaps would mean a big loss of time. In this case, you should copy the file to tape with the command "BINCOPY", that incerases the length of certain gaps in the file. (More info later.)¢¢¢ DOS COMMANDS ON TAPE¢¢ The CP-commands of BW-DOS are mostly working on tape. The commands that doesn't work are these ones that use special disk-oriented functions: MENU, UNERASE, BACKUP, MOVE, MSDOS, BOOT, CHVOL, XFSIO, FORMAT, PROTECT, UNPROTECT, RENAME, ERASE, CREDIR, DELDIR, CWD, DIRMAST, CHKDSK, HEXEDIT, and AUTOCWD. Use of such commands on tape is a nonsense anyway... But these commands may become useful also while working with no disk drive - when you'll use a Ramdisk.¢ The batch files and HardCopy function works with tape, but without of a Ramdisk or a disk drive, it's almost senseless. Because the tape handler can't open more files at the same time, the working batch file will block reading of commands and other files.¢ Some commands have different functions for disk and tape:¢¢DIR [B:][filename]¢DIRS [B:][filename]¢ (Internal commands)¢ These commands are useful for the orientation on tape. Both the commands have the same function for tape: It'll read one block (any block that match the file-specification), and display name of the found file followed by serial number of the block in the file. When the file was recorded with double blocks, a little star will appear in front of the name. Because of compatibility, the listing keeps the syntax of a disk-directory - including the "FREE SECTORS" counter (it's senseless on tape, but there are programs that needs it while interpreting such a listing).¢¢COPY source destination¢ (External command)¢ The "COPY" command works for tape-files too, of course. But it's important to use the new version, found on BW-DOS 1.30 master disk or in the "Update 2" package. The older version can't carry the original filename from tape (so you must allways type both the filenames - source and destination), and it also can't copy directly from tape to tape. This is also true for the internal "COPY" in SpartaDOS.¢ While copying directly from tape to tape, you can only work with files that fit into the free memory at once. The maximum length depends on the version of DOS, installed resident commands, and also the status of internal Atari-Basic (or other cartridge installed). To get an approximate number, you can subtract MEMHI - MEMLO - length of the "COPY" program. (First two numbers are shown by the "MEM" command, the last one comes from a disk-directory.)¢¢¢ TAPE BOOT¢¢ BOOT is loading of the DOS after power-on. With B-TAPE, the boot may be also executed from tape.¢¢ Boot loader¢¢ The first file on a boot-tape must be the Boot loader. It is a little program that loads the DOS itself and allows also loading of necessary residents, such as "BTAPE", "RAMDISK" etc. The Boot loader is stored in the same format as common tape-games to allow easy booting of the tape.¢¢TAPEBOOT (C|T)¢ (External command)¢ This command records the Boot loader to tape. With the "C" parameter, you'll get a common boot-file in the "C:" format - such a file may be easily booted by holding down the <START> key during power-on. The length of this loader is 14 blocks.¢ The "T" parameter was included especially for czech users. With this parameter, the "TAPEBOOT" command records the same loader in the format "TURBO 2000" - the very first version of the "Turbo" system. This is useful for the users, who own a cartridge with Turbo 2000 loader (such cartridges was sold here in the czech republic for several years).¢ The Boot loader is allways the same, so you can transfer it also with different tape-copiers.¢¢ Every files after the Boot loader will be in the B-TAPE format. The first of them must be a DOS file (a file that match the specification "X*.DOS"). It may be any version of BW-DOS, or SpartaDOS 3.2d, 3.2e, or 3.2f. The file is stored on tape without of any changes - you can copy the DOS from disk to tape and backwards without of problems.¢¢
