@Make@device @Define @define @define @heading @Appendix @label<-flop> @Index[Diskette] Floppy disks (flexible disks, diskettes), provide economical "removable media", i.e. a cheap way to store files offline such that they can be restored at a later time. Floppies come in two sizes: 8 inch and 5-1/4 inch diameters, and they can be single-@|sided, double-@|sided, or single-@|sided reversible. They can be hard-@|sectored (sectors are identified by holes punched in the disk) or soft-@|sectored (sectors are marked by recorded bit patterns). They can be single, double, or quad density. Microcomputers made by different manufacturers may employ any combination of these characterics in supporting their floppies; in general, floppy disks are incompatible between any two models of microcomputer, and sometimes even between software releases on the same model. Floppy disk drives are generally quite small and slow compared to more expensive media. A typical 5-1/4 inch floppy has a formatted capacity of about 150K bytes, turns at 300 RPM, transfers data at about 32K bytes per second, and has a seek (track access) time of 250 milliseconds. A large 3330-@|type disk drive may have a capacity 100-@|200 megabytes, turns at 3000 RPM, transfers data at up to 800K bytes per second, and has a seek time of 36 milliseconds. A typical magnetic tape system can store 40 megabytes on a 12-inch reel (at 1600 bits per inch), travels at 75 inches per second, and can transfer 120K bytes per second (access, of course, is sequential, not random). A floppy disk drive is vastly cheaper than a hard disk drive or a tape drive, and the floppy disk itself is significantly cheaper than a magnetic tape (a hard disk is quite large and is not normally considered "removable"). At $4 to $6 apiece, 5-1/4 inch floppies are the most affordable removable storage medium. Floppies consist of a flexible platter mounted permanently inside a square cardboard jacket. The platter turns inside the jacket. The machine's read-@|write head actually comes in contact with the surface of the platter through a slot in the jacket. The rubbing of the platter against the inside of the jacket and the read-@|write head can cause the the floppy to wear out after prolonged or repeated use. The jacket, in turn, is often kept in a paper envelope. The floppy is taken out of the paper envelope and inserted in the drive with its jacket on. Floppies should never be removed from their cardboard jackets. The shiny surface of the diskette should never be touched; always handle diskettes by their jackets. Diskettes should be stored in box or solid container. Never have the diskettes in their drives while the power is being turned on or off. Don't bend or otherwise mutilate the diskette. Don't allow liquids or moisture to come in contact with the diskette. Don't place diskettes where they might be subject to magnetic fields, temperature extremes, dust, or other contaminants. Don't write on the jacket with a ball point pen. @Appendix @label<-Brain> The @Index[Superbrain] SuperBrain is a Z80-@|based 8-bit @Index[Microcomputer] microcomputer manufactured by Intertec Data Systems Corp. It is equipped with two double-@|density 5-1/4 inch "minifloppy" @Index[Diskette] disk drives with a capacity of approximately 160K characters each. The smallest unit of storage on the floppy is 2K. CP/M allows up to 64 files to be stored on a single floppy. The SuperBrain runs the Intertec Data Systems version of the CP/M operating system. @AppendixSection The SuperBrain is a very simple machine to use. To start it, flip up the toggle switch located on the back. This is known as a @i. On a @Index[Cold Start] cold start the micro is automatically @Index[Bootstrap] "booted", i.e. the @Index[CP/M] CP/M operating system is loaded into memory from the system floppy and started. This should cause the following message to appear: @Begin 64K SUPERBRAIN DOS VER 3.1 FOR CP/M 2.2 A> @End The "@q(A>)" is the micro's prompt. It corresponds to the "@@" on the DEC-20. The letter to the left of the ">" (@q(A) in this case) indicates which floppy disk drive you are presently using (the one on the left is A). If you are on the B disk the prompt will be "@q(B>)". To switch from the A disk (which is the system disk, and to which you are "connected" by default) to the B disk, just type the command "B:" in response to the "A>" prompt: @begin A>@u B> @end @Index[Warm Start] There are two red keys located at the bottom corners of the main keypad. If these two keys are depressed at the same time a @i takes place; this means that whatever program may be running is interrupted, the operating system is reinitialized, and you are put back at CP/M command level. Warm starting the SuperBrain is like control-C'ing the DEC-20, except that CP/M programs can not be continued. For most purposes, there is no real difference between a cold and warm start. @AppendixSection @Label<-BrainFlop> @Index[Diskette] The SuperBrain uses a pair of 5-1/4 inch single-@|sided, double density, soft-@|sectored floppies, A (left) and B (right). The @Index[System Floppy] system floppy diskette should be mounted in Drive A, and should not normally be removed. The system disk contains the CP/M operating system and utilities, and the SuperBrain version of Kermit, Kermit-80. The SuperBrain should be turned off when not in use to minimize wear and tear on the system floppy. Drive B is available for user floppies. All floppies must be formatted before use (see Appendix @ref<-format>); the entire formatted capacity of the B floppy may be used for storage of user files -- no system files need reside on the B disk. @Index[Diskettes, Loading] Drive B is the vertical opening on the right. To insert a diskette in Drive B, open the drive by applying a very slight outward pressure on the small flat door located in the center of the opening. Insert the diskette with the label facing right, @i from the screen, notched edge up. Make sure the diskette is all the way in by applying a gentle pressure on the rear edge of the diskette. Once you are certain that the diskette is fully inserted, you may close the disk drive door by applying a slight pressure on the door, pulling it back in the direction from which it was originally opened. @AppendixSection @Index[CP/M] Once the micro has been started, you may give it commands. Commands may be typed whenever the prompt is present. Backspace or delete can be used to erase a character already typed. Control-X or control-U will erase the entire current line. Upper and lower case letters may be used interchangeably. All commands are terminated by a carriage return. CP/M has only five built-in commands, and they all deal with files; all other functions are done by invoking programs. CP/M file specifications are of the form @q(DEV:XXXXXXXX.YYY), where @begin @q(DEV:)@\is a @i, normally the A:@ or B:@ floppy. If omitted, the device name defaults to your connected diskette. @q(XXXXXXXX)@\is a @i of 8 characters. @q(YYY)@\is the @i, 3 characters. @end File names and file types may contain letters, digits, and some special characters, including dash, dollar sign, and underscore, but no imbedded spaces (just like TOPS-20 filenames, except that TOPS-20 file specification fields do not have trailing spaces). Upper and lower case letters are equivalent. "Wildcard" file-@|group specifications are permitted in file names and file types (but not device names) within certain contexts; a "@q(*)" matches a whole field, a "@q(?)" matches a single character, including space. Examples: "@q(*.F??)" specifies all files whose @i start with F and are 1, 2, or 3 characters long; "@q(F?.*)" specifies all files whose names start with F and are no more than two characters long (before the trailing spaces). The five CP/M commands are: @Begin DIR @\Lists the the names of the specified files. The default file specification is "*.*". Example: @w<"@q(DIR B:*.FOR)">. ERA @\Erases (deletes) the specified file(s); wildcards allowed. REN @\Renames a file; the new file name goes first, e.g. @w<"@q(REN NEW.FOR=OLD.FOR)">. SAVE@\Saves the specified number of memory pages into a file. You won't need to use this command. TYPE @\Types the specified file on the screen, e.g. @w<"@q(TYPE FOO.FOR)">. @End The most important programs are the following: @Begin STAT@\Gives statistics on disk usage. PIP@\@u

eripheral @unterchange @u

rogram. Copies files. In response to the "@q(*)" prompt, give a command of the form @example Wildcards ("@q(*)" for a whole field or "@q(?)" for a letter) can be used. Examples: "@q(A:=B:*.*)" to copy a whole disk, "@q(A:=B:*.FOR)" to copy all the Fortran programs from disk B to disk A. If the disk specification is omitted, your "connected" disk is assumed. Command line arguments are accepted, e.g. "@q(PIP A:=B:*.*)". @End For further information on SuperBrain commands and programs, consult the SuperBrain manual or a CP/M handbook. @AppendixSection @label<-format> @Index[Diskettes, Formatting]@Index[Formatting a Diskette] You must @i all new previously unused diskettes before attempting to transfer data to them. This is necessary because all information is stored on diskettes in what is known as @i which necessitates the writing of certain control information on the disks before user programs can be stored on them. Here's how to format a diskette. First, obtain a new blank diskette. Load the system diskette into Drive A and the blank diskette into Drive B. Boot the system. In response to the "A>" prompt, enter the command "FORMAT" at the keyboard. Remember to depress the key marked RETURN to enter the command. The operating system should now respond by asking you to select the type of diskette being formatted (S or D). This questions asks whether the diskette to be formatted is single sided or double sided. The SuperBrains at the Columbia Computer Center are single sided, so enter "S". The operating system will now ask you to put a fresh floppy in Drive B; answer "F" when this is done. At this point you will hear the disk drive reset to track 0 and begin the formatting process. When a disk is formatted, the read/@|write head positions to track 0 and rewrites each track (there are a total of 35 on each diskette). The screen will also display the current track that is being formatted; this number should range from 0 to 34. After the disk has been completely formatted, the operating system will respond by asking you whether to @i the operating system or whether you wish to format another disk. If you wish to format another disk, remove the newly formatted disk from Drive B and insert a new blank diskette into Drive B. You may now proceed to format this new diskette by once again entering the letter "F". If you do not wish to format any more diskettes, simply depress RETURN.