The first Mac system: Finder and file system

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<pre>The first Mac system: Finder and file system

In the origin of the myth of the primitiveness and worthlessness of Mac, its creators are to blame. They did their work too well. The Mac system was more complex and interesting than all popular systems of the time, inside. Outwardly, everything was very simple, and just worked.

And why does the user know the details of the anatomy and physiology of his personal assistant?

The worst kind of “experts” is the laymen who get the tops. Those who really owned the theme, Mac appreciated. They were not deceived by the simple interface, they found it very thoughtful, logical and convenient. “Today I saw what computers will be like in five years,” they said.

But the “experts” were perplexed: who needs this plastic “talking” box if it is absolutely impossible to understand it? There is no command line, no text files with scripts or with configuration settings. There is nothing, in general! Well, do not look at him “in the soul!”

Open the case? There is a sign on it: “Do not open, there is nothing interesting inside.” Someone did open it and, really, did not find anything interesting. Boards, chips …

I wonder what they were hoping to see there? A tiny alien, chained to a microscopic control panel, with a bowl of dried alien worms?

Finder and file system

The shell of the Mac's operating system from its first day until now is called Finder. “He who finds something.” On the border of the 80's and 90's, when the volumes of disk storage became large, an anecdote arose: Finder that finds nothing (Finder, which finds nothing), but in 1984, on a floppy disk with a capacity of 400 K, something was not easy to hide .

This is a classic Mac application written by Bruce Horn and Steve Caps. Bruce is a genius and perfectionist, a “lunatic psycho”. Work with him on one task could not and never. But in the fall of 1983, when nothing remained until the final and final deadline for the completion of the project, the Finder was “stuck.”

Steve Capps was able to find a common language with Bruce. The problems were absolutely objective, but they managed together. In December 1983 the Finder was ready for release. On that day, the Mac's developers staged the “Steve Caps Day” – everyone came dressed up as he dressed.

According to reporters, the main function of the Finder was managing the Mac's file system. Add to this definition only one word: “The main visible function …”. This is the implementation of the desktop metaphor, with documents and tools for working with them.

The file system of the first Mac was called MFS (Macintosh File System). It did not have a hierarchy of directories, it was “flat” as a bad joke, but for a floppy disk with a capacity of 400 kilobytes, much of it was eaten by the system, it was necessary.

Directories (for Mac's folders) in MFS on in fact, they were an illusion. They were visible only in the Finder. References to all file system objects were stored in one small, invisible file.

A hierarchical file system (HFS) was written much earlier, but was temporarily archived. Up to System 3.0 on Macs, only MFS was used.

The system floppy initially had two folders – System Folder and Empty Folder. In Empty Folder, the user could “clean” their documents and programs, as in a desk drawer. After taking the desired file and dragging it to an open or closed folder. Empty Folder could be renamed. And at the time of the renaming, there was a miracle: a new empty folder called Empty Folder immediately appeared on the desktop.

The file system of the very first Mac was called MFS (Macintosh File System), it was designed and optimized for unilateral 3.5- inch floppy disks with a capacity of 400 kilobytes, and laughed at it. She was “flat.” It contained only a “disk” (the same diskette) and files. Hierarchies of directories (folders if Mac) were not present.

When deleting Empty Folder (for this, it had to be dragged into the “Trash” and select “Empty Trash” from the Special menu. all that was in it, users were accustomed to the idea that this is not recoverable.In fact, if no new files were created after the destruction of these files, it could still be corrected with the help of a special tool – it really appeared, it seems to me , in 1985.

Theoretically, the file could be restored with the help of a hex editor, but it was beyond the limits of good and evil: it was necessary to find the lost file, correctly put its position on the disk in a notation, understandable to the “invisible file”, correct the information of the “invisible file” itself and not be mistaken anywhere – otherwise the system diskette stopped loading the system.To send it to the site by mistake (or for the sake of experiment), the file could be returned to the site using the Put Back command in the File menu. If “garbage has not been carried out yet.”

File names were intended for users, the file system used unique file identifiers (numbers) to identify them. In the names of files and folders, you could use absolutely any characters except the colon.

MFS could work with filenames up to 255 characters long, but the Finder limited the user's fantasy flight to poor 63. In one version (in 3.0, it seems) the length of the name the file was once again limited, this time by 31 characters. This restriction survived until 1998.

That is, if the “system font for outputting filenames in the Finder” knew the Cyrillic alphabet, the folder could be called “Ya. Favorites. For 1984..1987 years. ” And the documents in it, for example, “The Tale of the Runaway Bull.”

The content of the active (selected) window, if desired, could be printed, one-on-one. If there was a printer. Or send it by fax – if there was a modem and a fax sending program.

MFS could work with a disk space of up to 20 megabytes, or with 1400 files, at a time when the only available data store was one-sided floppy disks of 400 K capacity.

File system objects

In the previous section, I called the file system objects visible by the user to be the word “file”. This, in terms of designers (in the good sense of the word) Mac, sin. In the Mac system, there were no files, only applications, application documents and system documents.

The desktop metaphor is such a role-playing game.

The central element of this game was “documents”, double-clicking on their icon, they opened , and if the application running with them has not yet been launched, opened it. (It seems that now it is necessary to call “click” “click”, but I do not like this term).

You could start working with the application by double clicking on its icon – if there were no necessary documents on the disk, or if it was more convenient . Or if the application did not have any documents in principle (game, hexadecimal disk editor and so on).

Only system documents did not participate in the role-playing game, with a few exceptions, double clicking on their icons did not lead to any actions. They did not hide, and that's good. Did you have to install a driver, for example, a printer, in PC DOS? But on the Mac, the whole process was dragging the system document, for example “Image Writer LQ”, into the system folder. To remove a printer from among the working ones without removing its valuable system document (driver), you could remove its icon from the System Folder.

From where did the documents and applications know which icons to display them on the screen and how to open them? After all, there were no file extensions in MFS. If you did not know how to do it, but you asked yourself this question, I'm proud of you.

It was this search that the authors of the Finder title had in mind.

The text is stored in computers in the form of a sequence of numbers. In the era of classical OS, each symbol was designated byte, a number of 8 bits in length. Upper and lowercase letters, punctuation marks, a number, a space, etc. And also – “unprintable” characters like “line return”, “sound signal”, “jump to the next line” and the like. Today, much more boring encodings are used, but I will not tell you about them.

Macintosh team engineers came up with a data type, OSType, whose value was a number, but it was displayed as a sequence of 4 letters. OSType was used in the Mac system for the mnemonic designation of the most diverse entities.

The file type was displayed by two attributes of the OSType type, the first one representing its format (Type Code) and the second (Creator Code), in case the application file , stored the APPL mnemonics if the document is the type of the application that created this document. These are not all possible variants of the “creator”, the rest (system documents, drivers, etc.) are not of interest to us.

No matter how the file visible to the user appeared in the MFS or HFS repository, the system immediately recorded information about its attributes and an icon in a special file that is not visible to users. Double click on the document included the algorithm for finding the creator of this document – an application with a file type equal to the creator of the file. If there was no such disk within the disk, an application was found that can work with this type of documents.

Conflicts? Happened. But much less often than in PC DOS. On Mac'e, the file type was denoted by eight characters instead of three in PC DOS. The upper and lower case letters in the Mac's file type designation were different, and nobody forbade using any characters as unique values.

Multitasking

The system of the first Macs did not support multi-tasking. At any time, one program worked on the computer, either an application program, or a system program, that is, a Finder.

Meanwhile, during the development of the Mac, the need for utilities, which are always at hand, was quickly revealed. A calculator, an alarm clock, a map of the current keyboard layout and much more.

A solution was found. They called it Desktop Accessories, or DA's. Desktop accessories. By their nature, these were drivers of a special type. They lived in the RAM allocated to the running application. You could run any number of them, but you could easily damage the application that sheltered them.

DA's access was from the “Apple” menu, the content of which did not depend on the running application. DA wrote not only to Apple, but also to third-party developers.

To be continued.

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