Removable Disk Interchangeablity Standards, Floppy Diskettes
Disk interchangeablity removable diskettes floppy standards megabytes storage
power connectors high density heads sectors tracks write revolutions orb
| Floppy Diskette Data Storage Standards for PCs | |||||
| 360KB DSDD (1976) | 720 KB DSDD (1980) | 1.2 MB DSHD (1978) | 1.44 MB DSHD (1984) | 2.88 MB DSED (1988-IBM) | |
| Bit density (max) BPI | 5,876 | 8717 | 9869 | 17434 | 34868 |
| Bytes per Cluster | 1024 | 1024 | 512 | 512 | 1024 |
| Bytes per Sector | 512 | 512 | 512 | 512 | 512 |
| Clusters | 354 | 713 | 2371 | 2847 | 2863 |
| Coating Coercivity (oersteds) | 290 | 650 | 660 | 720 | 1200 |
| Coating Thickness (micrometers) | 2.5 | 1.9 | 1.3 | 0.9 | 0.9 |
| Dimensions | 5¼" | 3½" | 5¼" | 3½" | 3½" |
| Directory Entries | 112 | 112 | 224 | 112 | 240 |
| Directory Sectors | 7 | 7 | 14 | 14 | 15 |
| DOS Version Requirement | v1.0-3.0 | v3.2 | v3.0 | v3.3 | v5.0 |
| FAT Type | 12-bit | 12-bit | 12-bit | 12-bit | 12-bit |
| File Allocation Tables | 2 | 2 | 2 | 2 | 2 |
| Formatted Bytes | 368640 | 737280 | 1228800 | 1474560 | 2949120 |
| Heads | 2 | 2 | 2 | 2 | 2 |
| Interface | MFM | MFM | MFM | MFM | MFM |
| Magnetic Coating Type | Ferrite | Ferrite | Cobalt | Cobalt | Barium |
| Media Density | Low | Low | High | High | Extra-High |
| Media Descriptor Byte | FDH | F9H | F9H | F0H | F0H |
| RPM | 300 | 300 | 300 | 300/360 | 300/360 |
| Sectors | 720 | 1440 | 2400 | 2880 | 5760 |
| Sectors per Cluster | 2 | 2 | 1 | 1 | 2 |
| Sectors per FAT | 2 | 3 | 7 | 9 | 9 |
| Sectors per Track | 9 | 9 | 15 | 18 | 36 |
| Tracks | 40 | 80 | 80 | 80 | 80 |
| Tracks per Inch | 48 | 135 | 96 | 135 | 135 |
| Big Diskettes All of these drives READ & WRITE regular 720KB & 1.44MB diskettes! | |||
| Imation's 120MB LS-120 SuperDisk (1996) | Maxell's 120MB LS-120 SuperDisk (1996) | Sony's 200MB * HiFD * (1997) | |
| RPM | 720 | 720 | 3600 |
| Media Formulation | Metal particle | Metal particle | Metal particle |
| Heads | 2 | 2 | 2 |
| Tracks | 1736 | 1736 | 3482 |
| Tracks per Inch | 2490 | 2490 | 2822 |
| Sectors per Track | 51/92 | 51/92 | |
| Bytes per Sector | 512 | 512 | 512 |
| Formatted Bytes | 125829120 | 125829120 | 209715200 |
| * Note: They use different technical standards, so their Disks are NOT interchangeable! | |||
| Big Removable Disks | |||||||||
| Models | Zip | SuperDisk | HiFD | EZFlyer | Zip | Sparq | SyJet | Jaz | ORB |
| Companies | Iomega | Imation Matsushita Maxell Mitsubishi | Sony Mitsubishi Fuji Teac | SyQuest | Iomega | SyQuest | SyQuest | Iomega | Castlewood |
| Capacity | 100 MB | 120 MB | 200 MB | 230 MB | 250 MB | 1.0 GB | 1.5 GB | 2.0 GB | 2.2 GB |
| Popularity | ****** | ** | **** | ** | * | *** | * | ||
| Transfer Rate MBps | 1.40 | 0.12 | 3.6 | 1.8 | 2.4 | 3.7-6.9 | 5.6 | 5.4 | 12.2 |
| Seek Time | 29 ms | 29 ms | 49 ms | 13.5 ms | 29 ms | 12 ms | 12 ms | 10 ms | 10 ms |
| Buffer Size | 32 KB | 10 KB | 32 KB | 32 KB | 512 KB | 512 KB | 256 KB | ||
| RPM | 2945 | 720 | 3600 | 5400 | 2941 | 5400 | 5400 | 5394 | 5400 |
| R/W 1.44MB | No | Yes | Yes | No | No | No | No | No | No |
| EIDE | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes |
| Parallel SCSI | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| USB | Yes | Yes | Yes | No | Yes | Yes | No | Yes | Yes |
| PCMCIA | Yes | Yes | No | Yes | No | No | Yes | No | |
| Fast SCSI II | Yes | Yes | No | No | Yes | Yes | No | ||
| Standard 34-pin Floppy Drive Connector | ||||||
| Drive A: Connector | Drive B: Connector: | Function | Drive A: Connector | Drive B: Connector: | Function | |
| 1 | 1 | Ground | 18 | 18 | Direction (Stepper motor) | |
| 2 | 2 | Unused | 19 | 19 | Ground | |
| 3 | 3 | Ground | 20 | 20 | Step Pulse | |
| 4 | 4 | Unused | 21 | 21 | Ground | |
| 5 | 5 | Ground | 22 | 22 | Write Data | |
| 6 | 6 | Unused | 23 | 23 | Ground | |
| 7 | 7 | Ground | 24 | 24 | Write Enable | |
| 8 | 8 | Index | 25 | 25 | Ground | |
| 9 | 9 | Ground | 26 | 26 | Track 0 | |
| 16 | 10 | Motor Enable A | 27 | 27 | Ground | |
| 15 | 11 | Ground | 28 | 28 | Write Protect | |
| 14 | 12 | Drive Select B | 29 | 29 | Ground | |
| 13 | 13 | Ground | 30 | 30 | Read Data | |
| 12 | 14 | Drive Select A | 31 | 31 | Ground | |
| 11 | 15 | Ground | 32 | 32 | Select Head 1 | |
| 10 | 16 | Motor Enable B | 33 | 33 | Ground | |
| 17 | 17 | Ground | 34 | 34 | Unused | |
| Diskette Timeline | ||||
| Year | Capacity | Size | Sides | Density |
| 1971 | 1.0 MB | 8" | 1 | Single |
| 1973 | 256 KB | 8" | 1 | Single |
| 160 KB | 8" | 1 | Single | |
| 320 KB | 8" | 1 | Double | |
| 1978 | 512 KB | 8" | 1 | Double |
| 720 KB | 8" | 2 | Double | |
| 1.2 MB | 8" | 2 | Double | |
| 1976 | 160 KB | 5¼" | 1 | Double |
| 1976 | 180 KB | 5¼" | 1 | Double |
| 1978 | 320 KB | 5¼" | 2 | Double |
| 1978 | 360 KB | 5¼" | 2 | Double |
| 720 KB | 5¼" | 2 | Double | |
| 1978 | 1.2 MB | 5¼" | 2 | High |
| 1980 | 720 KB | 3½" | 2 | Double |
| 1984 | 1.44 MB | 3½" | 2 | High |
| 1988 | 2.88 MB | 3½" | 2 | Quad |
| 1996 | 120 MB | 3½" | 2 | Ultra-High |
| Acronyms / Glossary | |
| ATAPI | AT Attachment Packet Interface |
| Coercivity | The intensity of the magnetic field needed to reduce the magnetization of a ferromagnetic material to zero after it has reached saturation. |
| DSDD | Double Sided, Double Density |
| DSHD | Double Sided, High Density |
| DSED | Double Sided, Extra-High Density |
| EIDE | Enhanced IDE |
| FAT | File Allocation Table |
| GB | Gigabyte - 1,000 Megabytes - 1,000,000,000 bytes (10 to the 9th power) |
| IDE | Integrated Device Electronics |
| IEEE | Institute of Electrical and Electronics Engineers |
| KB | Kilobyte - 1,000 bytes (10 to the 3rd power) |
| MB | Megabyte - 1,000,000 bytes (10 to the 6th power) |
| MBps | Megabytes per Second |
| MFM | Modified Frequency Modulation |
| micrometers | Micron or micrometer (um): one-millionth of a meter. |
| ms | Millisecond or msec. One thousandth (10 to the -3rd power) of a second. |
| Oersteds | The centimeter-gram-second electromagnetic unit of magnetic intensity. |
| PCMCIA | Personal Computer Memory Card International Association |
| RPM | Revolutions per Minute |
| SCSI | Small Computer Systems Interface |
| SPT | Sectors per Track |
| TWAIN | Technology Without An Interesting Name |
| USB | Universal Serial Bus |
Disk interchangeablity removable diskettes floppy standards megabytes storage
power connectors high density heads sectors tracks write revolutions orb
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Created 12:24 AM 10/8/00
Suggestions or comments: EricAArnold@yahoo.com
Copyright © 2000 Eric A. Arnold
Last Modified on: 7:26 PM 1/25/02