Operating systems are for computers, tablets and smartphones and ... for calculators. But not simple, but programmable, such as we recently talked about. Texas Instruments developed calculators, and third-party companies created applications for them. Isn't it very similar to modern ecosystems of iOS and Android mobile platforms?
One of such third-party firms, Detached Solutions, is known for having created not something, but an operating system for programmable calculators. Moreover, judging by the news of the company's website, applications for programmable calculators were developed until the fall of 2009. It was almost yesterday!
Strictly speaking, MirageOS, to which our today's historical excursion is dedicated, is a shell for other TI-83 + / TI84 + calculators. It turns out a fun word game. The person sees the name MirageOS and reads it like: the Mirage operating system. But in reality it means: the mirage of the operating system.
What is MirageOS?
MirageOS is an application for the TI-83 Plus and TI-84 Plus programmable calculators, which plays the role of a shell and executes the Z80 assembly language and the TI-BASIC programming language, a dialect of the world-famous BASIC, known to many for computer science lessons. MirageOS significantly expands the capabilities of both the users of these calculators and the programmers who create applications for them.
Although MirageOS looks like a full-fledged operating system, it is not a replacement for the native OS of these TI-OS calculators and works in conjunction with it. It was called this because it is like a mirage: it resembles the operating system, but it really isn’t.
MirageOS features
MirageOS allows you to run programs in multiple formats. In its native format, as well as ION, BASIC and TI-OS ASM.
Program Manager - a built-in powerful graphical user interface of the program shell displays all programs compatible with it in the form of a scrollable list. Sorting is done by program name. There is a large set of commands that allows the user to conveniently organize and manage their programs. The program can be renamed, moved to additional media, returned from additional media, protected from editing by TI-OS and unlocked. The program can be hidden from display in the PRGM menu and returned to the visible state. Function Bar allows you to see the free balance of operational and permanent memory.
MirageOS supports advanced user interfaces, a kind of analogue of modern plug-ins. This allows the programmer to determine for himself how the program is displayed on the screen, how it will look on it. In addition to the four graphical interfaces, there is also a command line. I must say today some users prefer the command line GUI. To meet such lovers, just go to any forum dedicated to Linux.
MirageOS supports program folders. The user can group their programs in folders. In each folder, programs are sorted by name. Thus, programs do not lie in bulk in the root directory, but neatly occupy their places in user-created folders. The user can give folders arbitrary names, rename and delete them. Programs can be moved from folder to folder. In the program manager, folders are displayed as a list. The folder can be “open” or “closed”. This means that its content will or will not be displayed.
Arbitrary sort of folders. The user can sort the programs in all their folders. The function of automatically sorting programs in folders may be slow. If desired, it can be turned off.
MirageOS takes care of the battery and the amount of energy in it. The shell starts in energy-saving mode and only when the user presses one of the buttons of the calculator enters the operating mode. The shell supports Auto-Power-Down (APD, Auto Power Off). The calculator running MirageOS will turn off after three minutes of inactivity. If you press the ON button, the calculator will be turned off. When you press this button again, the calculator turns on and loads the shell into memory. A kind of system state recovery after a reboot.
MirageOS supports long descriptions not only for assembler programs, which is typical of other shells, but also for BASIC. And this is an innovation, characteristic at the time of creation only for MirageOS version 1.2. Long descriptions can be displayed in the search process through the list of programs.
The shell allows you to use icons of 15 x 15 pixels for MirageOS native programs. For the most part, these icons are visible in the Buttons Interface display mode (as buttons), but are also visible in the program manager.
Password protection. A sort of operating system mirage settings panel called Options Screen gives the user the ability to customize many of the parameters of both the MirageOS and the native TI-OS calculator operating system. Including the user can protect your calculator with a shell login password from TI-OS. However, this feature is positioned more as protection against inept pens who want to play around with the device than as a serious tool for ensuring information security.
Hotkeys are also supported by the native TI-OS operating system. MirageOS only expands their field of application. For example, you can call the mirage shell from TI-OS by holding the ON button while pressing APPS. To turn off the power of the calculator at any time, without turning to the Homescreen main screen, it is enough to first press the ALPHA button and then ON. Suppose a programmer writes a program in the BASIC editor and he urgently needs to turn off the calculator. He does not have to spend time on navigation. Another hot key combination is used to protect the Memory Menu. If this option is enabled, entering the memory menu using the 2nd + Mem key combination will not work. This allows you to protect yourself from deleting important processes from the memory, in particular, AppVar, which contains the user password for accessing the shell.
Interrupter tasks in programs. One of the most significant features of MirageOS is the function of performing tasks in the process of running previously launched applications, a kind of prototype (or mirage?) Of multitasking. Special hot keys allow you to perform an additional task at any stage of the current program execution. For example, in the course of work, you can change the image contrast, turn off the calculator's power, resume the program, return to the shell or to the main screen at any time, increase or decrease the speed of the program, and even place a screenshot on the calculator screen. This feature does not work in Basic programs, only in some ION programs, and in almost all native MirageOS programs.
Development of programs in assembler. MirageOS simplifies the creation of ASM programs because it gives the programmer access to more subroutines than ION. These are general purpose routines, well optimized for speed. Recall that the memory was very small and among programmers it was considered the rule of good form and high professionalism to write almost microscopic programs. So, with the help of MirageOS, the assembler programs become even smaller, since they can use the subroutine library by referring to it. And this means that some of the program code does not have to be included in the text of the program itself. In addition, in the MirageOS program, you can embed a call to third-party program code.
MirageOS also has a number of hidden features that optimize the work of programs in the operational and permanent memory of the calculator. The shell is located in the permanent memory. And this means that the RAM is free and remains at the disposal of programs in assembly language, which can reach huge sizes, approximately 24 Kb! Imagine this incredible power! MirageOS allows you to run programs that are moved from permanent memory to an additional storage medium. This is done by moving information into memory.
Some programs waste their memory, writing down their latest changes. For example, who scored more points in the game. MirageOS allows you to prevent programs from recording changes in their status. This, of course, has a side effect: the new data will not be saved. Today it is difficult to imagine that such an opportunity was once needed. But the fact remains that if 24 kilobytes is a huge program, you had to save every byte.
And, finally, another feature that distinguishes MirageOS from the preceding shells for programmable calculators. It has no restrictions on the number of programs defined by it. The only limit is the amount of available memory.
Did it surprise you that our narrative flowed not in the past, traditional for historical materials, but in the present? The fact is that there are still those who like to tinker with programmable calculators today and for some people this information does not refer to the forgotten “yesterday”, but to the actual one today.
Source: Detachedsolutions.com
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