dskutil(1)

💾 dskutil — the sector editor that's lowkey iconic 💅

okay bestie, so this is dskutil(1), and it lives in the Emulators section of the manual. she's a simple sector editor for discs and disc images, and honestly? she's giving vintage-but-thriving. ✨

✨ NAME ✨

dskutil — a simple sector editor for discs and disc images. (yes the original spells it "edtor", no we are not fixing it, we love her exactly as she is 🫶)

🌸 SYNOPSIS 🌸

dskutil [-type TYPE] [-side SIDE] [-comp COMP] [-dstep] [-retry COUNT]
[-format FMT] DISKIMAGE

🦋 DESCRIPTION 🦋

So dskutil is an interactive, command-driven sector editor, and she's patterned after the venerable CP/M sector editor DU90. Which, yes, explains a lot of her little idiosyncracies — for example, the way that commands deal in logical track numbers but physical sector numbers. That's just her vibe, iykyk. 💀

💖 OPTIONS 💖

• -type TYPE — picks which LibDsk driver gets used to access the disc. Your choices, queen:
  • auto — select according to the disc image file. This is the default. ✨
  • dsk — use the DSK (CPCEmu format) image driver.
  • edsk — use the extended version of the DSK format.
  • floppy — use the floppy driver.
  • myz80 — use the hard disk (MYZ80 format) image driver. (This format cannot be autodetected.)
  • cfi — use the CFI (DOS fdcopy format) image driver. (This format cannot be autodetected.)
  • apridisk — use the ApriDisk image driver (from the utility of the same name). (This format cannot be autodetected.)
  • raw — use the raw driver.
• -comp COMP — selects the compression method used on the disc image file. ngl this one has no effect when reading a floppy disc, so don't come for her.
  • auto — detect from the first few bytes of the file. This is the default.
  • sq — Huffman coded (SQ / USQ).
  • gz — Gzipped (gzip / gunzip).
  • bz2 — Burrows-Wheeler compressed (bzip2 / bunzip2).
• -side SIDE — decides which side (0 or 1) of the source disc gets scanned. If you don't pass this option, both sides get scanned. we love a thorough queen 💅
• -dstep — double-step the source drive (used to read 360k discs in 1.2Mb drives). Only supported by the Linux floppy driver. no cap.
• -retry COUNT — sets how many times to attempt a read/write/format in case of error. she's persistent, she's resilient. 🫶
• -format FMT — do not autodetect the disc format; use the named format instead. The format need only be an approximation to the actual format used by the disc. it's giving "close enough is fine, bestie".
• -first CYL — start scanning at the specified cylinder.
• -last CYL — scan up to and including the specified cylinder.

👑 COMMANDS 👑

Here come the single-letter commands, and they are so much. Operands in brackets like [filename] are optional. Numeric inputs show up as nn for decimal and xx for hex — and in either case, prefixing the number with # selects the alternate number system. 😌

Multiple commands on a line are allowed, separated by semicolons. periodt.

• +[x] — increase the current sector number by [x] and read the resulting sector, incrementing the track if necessary.
• -[x] — decrease the current sector number by [x] and read the resulting sector, decrementing the track if necessary.
• # — display the disc geometry for the current drive/disc image. (iconic.)
• $[variable[=value]] — view and amend the geometry. $ all by itself shows all possible variables with their current values; $variable shows the value of one variable; and $variable=value sets a new value. 🎀 Note that changing the size of the sector with $secsize=nn will cause the current sector buffer and clip buffer to be cleared.
• =ascii — search for an ASCII string, starting at the current sector. Hex codes can be included in the ASCII by surrounding them with angle brackets — for example, to search for the word "Hello" at the start of a line, you could use =<0A>Hello. The search string is case-sensitive.
• < — save the currently-loaded sector to a clip buffer.
• > — restore the contents of the clip buffer to the current sector buffer.
• ? — display a command summary.
• A[from,to] — dump the contents of the sector buffer as ASCII. If from and to are included, then only values between those offsets will be shown.
• CHoffset,value,value,value... — change bytes in the current sector buffer. The offset and values are in hex.
• CAoffset,ascii — replace bytes in the current sector buffer with an ASCII string. As with the = command, the ASCII can contain embedded hex bytes in angle brackets.
• CHfrom-to,value,value,value... — the same as CH above, but fills the range from from to to with the byte sequence, repeating or truncating it as necessary.
• CAfrom-to,ascii — the same as CHfrom-to, except that the byte sequence is specified as ASCII.
• D[from,to] — dump the contents of the sector buffer as ASCII and hex.
• Gxx — go to logical sector number xx.
• H[from,to] — dump the contents of the sector buffer as hex.
• Kfilename — save all "yanked" sectors (see Y below) to the specified file. This also clears them from memory. bye babes 👋
• Lfilename[,type[,compression]] — open a new drive or disc image. If this has a different sector size from the current sector size, the sector buffer and clip buffer will be cleared.
• N[geometry] — change geometry. N by itself re-runs the automatic probe; N with the name of a geometry selects one of the formats known to LibDsk.
• R — (re)read the current sector.
• Snn — set the current sector number, and read.
• Tnn — set the current track number. Does not read.
• V — compare the contents of the sector buffer with the current sector on disc.
• W — write the sector buffer to disc. 💅
• X — leave dskutil. (the goodbye button, she's emotional about it 😭)
• Y — append the current sector to a "yank" buffer. It can then be saved with the K command.
• Z[nn] — sleep for nn seconds; if nn is not present, sleeps for one second. nap queen. 💜
• /nn — This must be the last command on a line. It repeats the preceding line nn times.

💀 BUGS 💀

• On platforms with no sleep(3) function, the Z command works by busy-waiting. she's trying her best okay.
• Commands are always input using fgets(3), even when the host system provides a more sophisticated input method such as readline(3). not her choice, not her problem.
• While the current feature set is a fairly good match for DU90 (less the features specific to the CP/M filesystem) it doesn't cover all the features of LibDsk. no cap, that's just the truth.

🌈 AUTHOR 🌈

John Elliott <seasip.webmaster@gmail.com>. 💖

okay that's the whole page bestie, and the sign-off goes like this: this is Version 1.5.9, dated 17 September 2018, and she lives in the Emulators section. slay, hydrate, and always remember to R before you W. ✨🎀🦋