afda6ca83b1ea6b1d92ee80983b0fb3a2899fceb
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Commits
| Author | SHA1 | Message | Date | |
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  AnachronautandClaude Opus 5
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afda6ca83b |
Finishing says nothing, which is what finishing looks like
The shell printed "finished" every time a program gave the machine back. That made sense when starting a program and getting the machine back was most of what the machine did and the prompt was the only other thing on the screen. Under a listing, between two commands, it is noise. And it was printed whatever the program made of it, so a program that had just explained what went wrong was answered with the word "finished" - "there is no such directory: nowhere" and then, immediately, "finished". The prompt coming back is what says a program is over. It is the same argument osLastStatus is made of: a program that failed has already said so in words, and anything the shell adds beside that is the shell talking over it. A program that FAULTED still says so, because the fault screen printed in red above and a program that is gone should not look like one that ended. A NEWLINE ONLY IF ONE IS WANTED. A program that stopped part way along a line would leave the prompt sitting in the middle of its last output, which the word used to prevent by accident. The console knows which column the cursor is in, so the shell asks - where a blank line printed every time would be right about half of the time, and an empty directory listed with ls would be followed by a blank line for no reason. Fifty nine recorded sessions lose the word. Two of them move a cursor up a row with it, which is the same fact seen from the screen. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |
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AnachronautandClaude Opus 5
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323d7a0330 |
A listing says what is left of the disk, and what will fit
dir said what was there and nothing about what was left. SplitDisk has printed the free figure since it was written, so the machine's own listing was the poorer of the two implementations at describing the same disk. 43 files, 3 directories 46 of 64 entries, 1893 blocks free Entries first, because they are the ceiling nobody notices until they hit it: a disk of small files runs out of directory slots long before it runs out of blocks. COUNTED RATHER THAN ASKED. The superblock keeps a free count and this file calls it "a note rather than the truth" in three places. sbfsSpace reads the whole directory table instead, which costs a read per directory block and is the answer rather than a guess. SplitDisk goes on reading the note and saying when it is stale, which is the right place for that check - the host tool is what you audit a disk with. ---- And it is a fact about the disk, not about where you are ---- The first version added the blocks up as the LISTING walked past them, which cost no extra read and was wrong: that walk stops only on entries in the working directory, so the same disk came out as 1,996 blocks free from the root and 2,025 from /Apps. Comparing against SplitDisk is what said so, which is what having two implementations is for. ---- The longest run, which is what decides whether a file fits ---- 4 of 16 entries, 37 blocks free the longest run is 25 Files are laid down contiguously, so the free total does not say whether a file will fit. Both implementations learn it, from one specification. Said only when it differs from the free total. Deleting is what fragments a contiguous store, and a disk that has only been appended to has one gap at the end - so on a healthy disk this is silent, and a line that appears only when something is wrong is a line somebody reads. There is no sort on this machine and the entries are in no order, so a candidate walks the disk: each pass finds the used extent nearest at or after it, and anything the candidate stands inside pushes it to the far end and starts the pass again. The same trick allocating uses. So it costs a pass per gap rather than per file - nearly nothing on a disk with one gap, more the more fragmented the disk is, which is the right way round. holes.img is six files with the second and fourth deleted, because no other disk here can show any of this: none of them has ever had anything deleted from it. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |
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AnachronautandClaude Opus 5
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736037462e |
The shell edits the line it is given
Three different things used to do this job, and which one you got depended on where the machine was running. On a terminal the host held the line and did the echoing and the backspacing; behind a window the console's own gatherer did it; from a file nothing did it at all. One job, three implementations, none of them in the system - which is why there was no way to move about in a line and nowhere for a history to live. So editLine does it. Key mode while a line is being read and line mode straight after, so nothing else in the system and no program calling osReadLine notices anything changed. Left and Right, Home and End, Backspace for the character before the cursor and Delete for the one under it, and anything typed goes in where the cursor is with the rest of the line moving along. Ctrl-D means the end of input again, on an empty line, because that was a thing the terminal did while it was holding the line and it is not holding it now. Same trade as the echoing. MOST KEYSTROKES DRAW NOTHING BUT THEMSELVES. A character typed at the end of a line needs no cursor moved: printing it is the whole change, and a backspace there is three ordinary bytes. That matters beyond speed - moving the cursor by hand is what a terminal is TOLD about, in an escape sequence, so redrawing on every keypress would fill every recorded transcript in this suite with them. The line is only reprinted when something happened in the middle of it. Where the line STARTS is worked out backwards from where printing ended, rather than trusted from what was remembered. That is what makes it survive the screen scrolling: a line printed on the bottom row moves everything up by one, and a remembered row would be one too low from then on. The command line holds 127 characters, up from 63. The limit started to be felt the moment a line could be moved about in. 58 recordings changed, and every one of them by the echo. THE PROOF IS NOT A HEURISTIC: a CosmOS built with the echo silenced reproduces 187 of the 188 recordings byte for byte. The one exception is cosmosTyped, the backspace test, where the rub-out marks now come from the shell instead of from the console's gatherer - same marks, different author. cosmosEditKeys is the new test, and every line in it is typed wrong and then corrected with a different key. Its last line is eighty six characters at a prompt in column two on an eighty column screen, so the line runs onto the row below and the shell has to find the start of something it can no longer see; breaking either half of that arithmetic fails it. Also: agree.sh looked for "> the same", anchored to a prompt that no longer precedes what a command prints. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |
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AnachronautandClaude Opus 5
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04f1ffabd4 |
A disk made of memory, brought up by whoever owns it
THE MACHINE SUPPLIES BLOCKS AND SAYS WHAT A DRIVE IS. It says nothing about filesystems, which is what leaves room for a system that would rather have its own - and is why the volatile bit is a fact about the hardware rather than a promise about SBFS. 0x26 what the selected drive is: bit 0, contents do not survive 0x27, 0x28 how many blocks it has --ram-disk N a drive of N blocks with memory behind it A drive of memory selects, reads, writes and has a size like any other, and a program cannot tell the difference except by how fast it was. The one thing it cannot work out for itself is that the contents are volatile, because an empty disk and a volatile disk look identical from outside. THAT BIT IS THE DIFFERENCE BETWEEN A DRIVE A SYSTEM MAY FORMAT ON SIGHT AND ONE IT MUST NOT. CosmOS formats a volatile drive it cannot read, because there was never anything on it to lose, and leaves every other unreadable drive alone - an unformatted floppy is not an invitation, it is a blank floppy. Removing that check formats somebody's blank disk, which is checked rather than asserted: cosmosBlankDisk boots with one and requires it to be refused. So CosmOS grew a format. The size comes from the drive rather than from a superblock, since a superblock states a size too and that is no use on a disk which has not got one yet. Sixteen directory blocks, 128 names, chosen rather than worked out: a scratch disk runs out of names long before room, and this machine cannot divide. The RAM disk is no faster on this emulator by default, and that is honest rather than disappointing: the emulated disk has no seek time unless asked for one. With --disk-cycles 10000 the same copy is 7.94M cycles against 8.70M, the difference being every write. run.sh takes "ram:2048" where an image name goes, which needs no removing between runs because there is nothing to remove. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |