Always remember that whenever the RESET button is pressed, everything in the computer’s memory (RAM) is cleared. You should therefore always make sure that you have completely finished with any program in the +3’s memory, before you press the button. IMPORTANT – Whenever you have finished using the +3, always disconnect the power supply unit from the mains supply socket (having first removed any disk from the disk drive). Don’t worry if you know nothing about BASIC – we’re not going to do any programming just yet – we’ll simply return to the opening menu again.

Write protection

There is a special format of the COPY command as follows… The name before the word TO is known as the source filename, and the name after TO is the destination filename. The letter P is short for https://www.quick-bookkeeping.net/ protection (against overwriting). The PLAY command will simply ‘hop over’ any comments in the string. Write down the numbers corresponding to the effects you want, and then add them together.

Cassette unit

CODE 16384,6912 is such a useful area of memory (the screen display) to save and load, that a special function (SCREEN$) has been provided to represent it, so you can type (for example)… Similarly, if we wanted to list all the files that began with a letter S and had a type field that began with the letter B we would use… We will now save several copies of our simple example program using different names, so that you will gearing ratios: definition types of ratios and how to calculate be able to see what the various forms of the CAT command will produce. If either of these weren’t listed with the above CAT command, add their name to the list below. There are special forms of SAVE and LOAD which can be used to change the default drive. When SAVE or LOAD is followed by a filename that contains nothing but a drive letter and a colon, the drive identified by the letter is then made the new default drive.

1. The area that was the printer buffer in 48 BASIC mode, is used for extra system variables in +3 BASIC mode in much the same way as it was on the Spectrum +2.
2. The second example has half the difference between notes, and this is called a semitone.
3. A read-only file cannot be written to, erased or renamed.
4. Graphical representation helps in solving complicated equations.
5. There is a special device to get over this – whenever you wish to write a string quote symbol in the middle of a string, you must write it twice, like this…

What are the 4 Quadrants in a Graph?

This feature can be extremely useful as it allows you to ‘fix’ a program that has stopped due to errors, and then CONTINUE from that point. Although the screen is filing income tax return late blank, the program is running – executing line 200 over and over again. This looks all set to go on forever unless you pull the plug out or reset the computer!

Extended disk parameter blocks (XDPB)

This will allow +3DOS routines to be called without having to move it again. Consequently, it will be necessary to switch both ROM and RAM, and move the stack before and https://www.quick-bookkeeping.net/can-i-get-a-tax-refund-with-a-1099-even-if-i-didn/ after calling one of the entries in the DOS jump table. The following very simple example shows one way of achieving the desired set up in order to call DOS CATALOG.

The x-axis is one of the two number lines that make up a 2D rectangular coordinate system (or one of three in a 3D coordinate system). The +3 can connect to a very wide range of peripherals via the EXPANSION I/O socket at the back of the machine. Although this socket is much the same as on the old-style Spectrum 48K, there is no guarantee that a device which ran correctly on a Spectrum 48K will run on a +3. You should, therefore, before you purchase any expansion device or add-on, verify that it will work with the +3, and not just with a 48K Spectrum. Details of (parallel and serial) printer operation will be found in chapter 8 parts 21 and 22. Connect the other end of the lead (which is fitted with a Centronics style plug) into the socket on the printer.

The point at which the two axes intersect is called the origin. The coordinate plane was developed centuries ago (in 1637, to be exact) and refined by the French mathematician René Descartes. In his honor, the system is sometimes called the Cartesian coordinate system. The coordinate plane can be used to plot points and graph lines. This system allows us to describe algebraic relationships in a visual sense, and also helps us create and interpret algebraic concepts. Thus, to plot a point on a coordinate plane, we simply need to know the ordered pair.

The words SQUARES is just a name that you use to ‘label’ the program you are going to store on disk. To prevent confusion, everything stored on disk must be given a name. These names (called filenames) are a little different from those that you may use when storing programs on tape. Firstly, PLAY is just as happy with a string variable as with a string constant. In other words, providing that a$ has been set up beforehand, PLAY a$ works just as well as PLAY « O5DECcg ». In fact, using variables in PLAY statements has certain distinct advantages, and we shall be doing this from now on.

If you are using the calculator whilst working on a BASIC program, then any variables used by the calculator should be chosen so that they do not conflict with those used by the program itself. When you have selected the Calculator option, the screen will change to… This program sets up the +3 to play one of the most well-known and enduring of computer games. Arbitrary expressions are allowed everywhere (except for the line number at the beginning of a statement). The argument of a function does not need brackets if it is a constant or a variable (optionally subscripted or sliced). In (a), suppose the string expression has the value s$, then if the slicer is empty, the result is s$ (considered as a substring of itself).