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Diffstat (limited to 'floppy/README')
| -rw-r--r-- | floppy/README | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/floppy/README b/floppy/README new file mode 100644 index 0000000..403bc6f --- /dev/null +++ b/floppy/README @@ -0,0 +1,89 @@ +------------------------------------------------------------------------------- +Floppy Disk Sector Formatting +------------------------------------------------------------------------------- + +These captures contain example floppy disk contents and operation. + +Logic analyzer setup +-------------------- + +The logic analyzer was a Saleae Logic (fx2lafw) sampling at 4 MHz. + + Probe Floppy/Shugart bus + ------------------------------ + D0 Pin 32 (SS) + D1 Pin 30 (RD) + D2 Pin 26 (TRK0) + D3 Pin 24 (WG) + D4 Pin 22 (WD) + D5 Pin 20 (STP) + D6 Pin 18 (DIR) + D7 Pin 8 (IDX) + +The sigrok command line used was: + + sigrok-cli -d fx2lafw -c samplerate=8m \ + -C D0=SS,D1=RD,D2=TRK0,D3=WG,D4=WD,D5=STP,D6=DIR,D7=IDX \ + --time 3s -o <filename> + +ibm-144-hello.sr +---------------- + +The capture is of a pre-formatted IBM-compatible 3.5" 1.44 MB disk, modified +using Linux with: + + mkfs.fat -n HELLOWORLD <device> + mount <device> a + echo 'Hello, world!' > a/hello.txt + +The following FluxEngine command was used to read both sides of the first three +cylinders: + + fluxengine read ibm --1440 --decoder.retries=0 -c 0-2 + +That results in an image with (Cylinder,Head,Sector): + + 0,1,2 is the root directory + 0,1,17 is the hello.txt contents + +3.5" 1.44 MB disks use a data rate of 500 Kbps and MFM. + +micropolis-mod-ii-hello.sr +-------------------------- + +The capture is of a FlashFloppy-emulated double-sided 16 hard sector disk, +created on Vector Graphic, Inc's Vector 4 using CP/M with: + + format + # select drive B + pip b:hello.txt=con: + # Type: Hello, world!<enter><ctrl-z> + +The following FluxEngine command was used to read one side of the fifth and +sixth cylinders: + + fluxengine read ibm --1440 --decoder.retries=0 -c 4-5 --drive.revolutions=20 + +That results in an image with (Cylinder,Head,Sector): + + 4,0,0 is the directory + 5,0,0 is the hello.txt contents + +Micropolis Mod II disks use a data rate of 250 Kbps. Configuring IDX improves +its results. + +floppy-test-... +--------------- + +These are captures specifically created for testing and are much smaller than +full captures. + + micropolis-idx.sr: This capture is the time range 1.596-1.608s + extracted from micropolis-mod-ii-hello.sr. It + contains a sector that decodes improperly unless + observing IDX. + + floppy-test-ibm-hello.sr: This capture is the time range 1.699-1.709s + extracted from ibm-144-hello.sr. It contains the + contents of hello.txt + |