More about 8" floppies: recovering data from odd diskette formats I didn't even know existed!
CuriousMarc・12 minutes read
Antoine developed an adapter for an early 8” floppy diskette drive and discovered 11 major differences between 5-1/4” and 8” floppies, allowing PC reading. Eric successfully recovered all data from a Minnow disk, showcasing the process of reading and decoding the ancient format and overcoming challenges with HP computers and their 8-inch floppy drives.
Insights
- Developing an adapter for an early 8” floppy diskette drive allowed Antoine to connect it to a PC, showcasing innovation in retrofitting older technologies for modern use.
- Recovery of crucial data from an IBM 360 Minnow disk, despite its unconventional format, highlights the importance of reverse engineering, manual control, and specialized tools in preserving historical information stored on outdated media.
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Recent questions
What are the major differences between 5-1/4” and 8” floppy disks?
The major differences between 5-1/4” and 8” floppy disks include the physical size, storage capacity, and sector structure. While the 5-1/4” floppy disks are smaller in size and have lower storage capacity, the 8” floppy disks are larger and can hold more data. Additionally, the sector structure of the two types of floppy disks differs, with the 8” floppy disks having a hard sectored format with 32 sector holes.
Why was the IBM Demi Diskette considered a commercial failure?
The IBM Demi Diskette was considered a commercial failure due to its low storage capacity and high cost compared to competitors like Sony. Despite being an ancient format, the IBM Demi Diskette did not gain popularity in the market due to its limited storage capabilities and higher price point, leading to its lack of success among consumers.
How did Eric recover data from a Minnow disk for an IBM 370 model 135?
Eric successfully recovered data from a Minnow disk for an IBM 370 model 135 by reverse engineering an IBM proprietary drive, manually controlling it, loading heads, and retrofitting it for Minnow disk compatibility. By developing a half-step driver for 32 tracks per inch alignment, analyzing data with a logic analyzer, and decoding sector data, Eric was able to recover sector data bit by bit from the Minnow disk, showcasing the process of reading and decoding the ancient format.
What challenges did Eric face with Intel diskettes from an Intel Intellec MDS-80?
Eric faced challenges with Intel diskettes from an Intel Intellec MDS-80 due to their non-standard sector structure and MFM encoding. These 8-inch diskettes were unreadable by a PC, requiring a specialized solution like the Applesauce floppy disk controller to support the unique sector encoding. Despite most diskettes being unreadable, Eric managed to recover data from one diskette, prompting the need for an Applesauce system for successful reading.
How did Eric overcome challenges with HP computers and their 8-inch floppy drives?
Eric overcame challenges with HP computers and their 8-inch floppy drives by utilizing analog debugging skills, resourcefulness, knowledge of magnetic heads, and alignment expertise. Each HP computer failure presented unique obstacles that required Eric to troubleshoot and problem-solve effectively to successfully recover data from the 8-inch floppy drives. Through his expertise and determination, Eric was able to navigate the complexities of HP computers and their floppy drives, showcasing his technical prowess in overcoming challenging situations.
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Summary
00:00
"Adapting 8" Floppy Drives for Modern Use"
- Battled with an early 8” floppy diskette drive, connected it to a PC, and Antoine developed an adapter for it available on Tindie.
- Discovered 11 major differences between 5-1/4” and 8” floppies, but signaling wasn’t one, enabling PC reading after figuring out details.
- Showed 4 types of 8” floppies: single-sided, double-sided, single density, double density, and omitted hard sectored 8” floppy.
- Introduced IBM demi diskette, an ancient format, and discussed historical software on Minnow disk from IBM 370 and a weird Intel floppy.
- Examined a hard sectored 8” floppy with 32 sector holes, different right protect tab, and a 4-inch floppy prototype drive.
- IBM Demi Diskette was a commercial failure due to low storage capacity and high cost compared to competitors like Sony.
- Received an original IBM 360 Minnow disk for firmware loading, requiring different speed, track count, and encoding for reading.
- Reverse engineered an IBM proprietary drive, controlled it manually, loaded heads, and retrofitted it for Minnow disk compatibility.
- Developed a half-step driver for 32 tracks per inch alignment, analyzed data with a logic analyzer, and decoded sector data.
- Programmed to recover sector data bit by bit from the Minnow disk, showcasing the process of reading and decoding the ancient format.
13:45
Recovering Data from Vintage Floppy Disks
- Eric successfully recovered all data and sector info from a Minnow disk, crucial for an IBM 370 model 135, after realizing it rotates in the opposite direction of a standard disk. The disk contains essential IPL microcode firmware necessary for booting the machine. Despite the microcode being made up of commands rather than instructions, the bits are archived but their meaning remains unknown. Moving on, Intel diskettes from an Intel Intellec MDS-80, using MFM encoding and 8-inch diskettes, were unreadable by a PC due to a non-standard sector structure. An existing solution, the Applesauce floppy disk controller, supports this sector encoding. Only one diskette contained good data, prompting the user to acquire an Applesauce system for reading. This episode concludes the adventures with early 8-inch floppy formats, but more challenges await with HP computers and their 8-inch floppy drives, each failing uniquely, requiring analog debugging skills, resourcefulness, knowledge of magnetic heads, and alignment expertise to overcome.
