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-------------------------------------------------------------------------------
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
|
