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Translation of the article from the site of the programmer and lover of old iron Michael Slomkovski 3r33232.  
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An old MFM disk, MiniScribe 201? came to my hands, along with the controller. MFM is modified frequency modulation , and this technology is often associated with bulky hard drives from the era before the IDE /Parallel ATA. The ancient data stored on the disk (mostly MS Word 4.0 documents) had a certain sentimental value for the previous owner, so I decided to extract them. 3r33232.  
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Hard disk MiniScribe 2012 3r3207. 3r33232.  
The hard disk, the MiniScribe 2012 MFM, was probably produced in 1984. He stood in an IBM XT-compatible computer. This monster occupies two slots of ??? "and weighs more than two kilograms. As indicated in 3r3325. Instructions
, Its volume is simply amazing - as many as ten megabytes. The power connector is a standard Molex. The disk is connected to the controller card with two cables.
 
Specifications easy to find. In text file 3r33232. contains installation instructions; we may also need a list of compatible devices. 3r33232.  
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In theory, the controller is able to work with any drive that supports the ST506 /412 protocols, but in practice everything is not so simple. The list of bad sectors should be stored in the ROM controller. This requires special software. Often, a new drive starts working after connecting it with a new controller and performing low-level formatting. 3r33232.  
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3r375. 3r33232.  
Disk Controller WD1002A-WX1 MFM 3r33232.  
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The controller has its own BIOS, which is usually called
Option ROM . It is caused by the motherboard BIOS during the POST sequence. The code registers a hook on the INT 13 interrupt and as a result becomes accessible from DOS using the standard interrupt call. 3r33232.  
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The device 3r3207. 3r33232.  
Fortunately, I had an old AT motherboard (ATC-1020) with ISA slots and a Pentium processor. There was no radiator on the processor, but I installed the jumpers on the board so that it worked at minimum speed, and fitted the temporary radiator with an elastic band. I also installed a 32 MB DIMM RAM module on the board. 3r33232.  
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3r3398. 3r33232.  
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I didn’t have a graphic VGA card for either PCI or ISA, so I used 3r3103. MDPA 3r33232. with a special yellow monochrome display. The motherboard successfully recognized it, as seen in the photo. 3r33232.  
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To check the disk, I turned off the IDE controller in the BIOS and tried to boot. The disk came to life and even booted - hurray! 3r33232.  
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Downloading from PXE

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I assumed that in order to play with this MiniScribe disc, I would need utilities for DOS, so I decided to boot from MS-DOS diskette. Since it is inconvenient to bother with physical diskettes, I decided to use network boot. Fortunately, I had a PCI Ethernet network card with support for 3r3117. PXE
: 3com 3C905C-TXM
 
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To boot a PXE floppy image, you need a special bootloader. One of the most popular is PXELINUX, part of Syslinux, module syslinux from Arch Linux. On a Linux machine, you need to create a directory for network booting and copy
there.  
PXELINUX:
 
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cp /usr/lib/syslinux/bios/{ldlinux.c3?memdisk,pxelinux.0}.
mkdir pxelinux.cfg
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Then create a text file pxelinux.cfg /default with the following content:
 
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3r3144. default dos
 
label dos
 
kernel memdisk
 
append initrd = fdboot.img 3r33232.  
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The boot diskette image must be saved as fdboot.img. These files can be downloaded as ZIP archive . 3r33232.  
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A popular way to configure PXE boot is dhcpd and TFTP daemons. This is a complex task, but fortunately, I found a small and easy-to-use netboot server (aur /netboot under Arch Linux). It combines the capabilities of DHCP and TFTP servers. In my router, I ran it without shutting down the DHCP server, since they didn’t seem to conflict. 3r33232.  
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Run netboot in the directory where the PXE boot files are located. After the DHCP request, the server returns the pxelinux.0 * file. 3r33232.  
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netboot {broadcast IP} {local machine IP} {IP for client machine} {MAC pattern}
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{MAC pattern} must match the MAC address of the client network card. 3r33232.  
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For example, my address in the local network is ???.? the IP of my Linux machine is ???.10 and the MAC of my 3com card ends at 66:
 
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netboot ???.???.???.??? -66 3r321616.
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As fdboot.img, I used a standard MS-DOS ??? disk. Then I downloaded it all - and it worked! 3r33232.  
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Attempts to copy data from an IDE disk

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Since the MFM controller has its own BIOS, the drive was visible under MS-DOS. But I needed a drive to which I could copy the files. At first, I decided to try an IDE disk. The motherboard had two IDE channels. I connected a 40 Gb drive from Seagate. The system found it, but, unfortunately, after that MFM ceased to be available. Jumper games did not help. Perhaps there was some kind of conflict between the two disk procedures. 3r33232.  
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Copying data to a USB flash drive 3r3207. 3r33232.  
Then I tried a different approach. I installed a PCI USB expansion card and USB-ASPI drivers for MS-DOS. Now there was no conflict, and I managed to copy the entire disk to a USB flash drive! 3r33232.  
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xcopy c: d: /e /k
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Four expansion cards on the motherboard. From left to right: MDA graphics card, MFM disk controller, 3com Ethernet network card, USB expansion card. 3r33232.  
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As a result, I had more than two hundred Microsoft Word files for DOS, which I converted to RTF .