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  • Atari 8-Bit Computers: Frequently Asked Questions (7/31)

    From Michael Current@21:1/5 to Marc G. Frank on Sat Jul 11 11:02:10 2020
    [continued from previous message]

    TANDON (810T Analog) MPI (Pre-Analog & 810M Analog) FRONT Operated by a front latch. Operated by a door release BEZEL No diskette eject mechanism. Raise button.
    the front latch to access diskette. Contains a diskette eject
    Plastic guides and front latch mechanism.
    inhibitor position the diskette.

    UPPER Contains no pressure spring. Contains pressure spring
    ARM assembly.
    ASSEMBLY Adjust by turning the two nuts which Adjust pressure spring.
    secure the upper arm to the
    carriage.

    STEPPER Adjust by turning the cam screw at Adjust by loosening setscrew MOTOR rear of Drive Mechanism. to move Stepper Band Pulley. ADJUSTMENT

    TRACK 00 Adjust by monitoring increase and Adjust for 0.010 clearance. STOP decrease in waveform amplitude.

    WRITE Microswitch Assembly Phototransistor
    PROTECT
    CIRCUIT

    Manuals:
    - Atari 810 Disk Drive Operator's Manual C014760 (earlier units)
    - Atari 810 Disk Drive Owner's Guide C060056 (later units)

    Technical manuals: Atari 810 Disk Drive Field Service Manual
    - Preliminary (~190 pages)
    - FS015854 Rev. 1 July 1980 (~138p)
    - FD100003
    - July 1982 [Rev. 02]
    - Rev. 03 May,1983

    From winter 1980 to fall 1981 the 810 shipped with CX8101 Master Diskette (boxed; DOS I). From fall 1981 to May 1983 the 810 shipped with CX8104 Master Diskette II (boxed; DOS II version 2.0S or DOS 2.0S). Box contents for both are detailed elsewhere in this FAQ list.

    810 accessories from Atari:
    CX8100 5 Diskettes. (unformatted; marketed for use with 810 only)
    CX8202 5 Blank Diskettes. (unformatted; for 810/815 disk drives)
    Minimal production, see: http://www.myatari.com/ebay/815dt.html
    CX8111 Atari 810 Formatted Diskettes II (5 per box; retail box never shipped,
    but individual CX8111 disks shipped with other products including
    810 Master Diskette II (CX8104))
    - Format is equivalent to disks formatted with 810 drives containing
    the Revision C ROM.
    - Speculation: Product was released for users of older 810 drives
    with the Revision B ROM which could only create slower format disks.

    Third-party upgrades for the 810:

    Fast-Chip, by Binary Corporation, 1982
    - Disks formatted by an 810 with Fast-Chip utilize an improved sector
    layout which is more efficient than those created by standard 810 drives.
    - 30% faster formatting for earlier 810 drives (prior to "ROM C"), or
    10% faster formatting for 810 drives with "ROM C" (Nov. 1981 or later)

    Happy 810 Enhancement, by Happy Computing (Richard Adams), 1982
    - Company name became Happy Computers, Inc. in 1983
    - Three versions: HE810S-X for early 810 drives (no Data Separator)
    - Upgrade includes a data separator
    HE810S-L for pre-Analog 810 drives with Data Separator
    HE810S-H for 810 Analog drives
    - RAM buffer: 1 track / 2304 bytes / 18 sectors
    - "Happy" Warp Speed standard high speed "Reads disks up to 3 times faster
    than standard 810" with any software; supporting software also supports
    buffered fast write with verify
    - Navigate/edit/create nonstandard format disks
    - 1982-1983 units shipped with Happy Backup Program (single drive) disk,
    including standard 810 ROM emulator and diagnostic program
    - Software sold separately, 1982-1983:
    - Multiple Drive Happy Backup Program
    - Happy Compactor Program
    - Warp Speed Software disk included (1983- ), contains Warp Speed DOS
    (modified Atari DOS 2.0S), Diagnostic, Sector Copier, Happy Backup, Happy
    Compactor, Multi Drive Happy Backup, Tracer
    - Software sold separately, 1982- :
    - Happy Customizer Program (create non-standard disks track-by-track)
    - 810 Version 7 Upgrade, hardware upgrade by Happy Computers, required for
    1982-1985 units to run Happy Warp Speed Software Rev 7, as well as other
    software sold separately by Happy Computers:
    - Warp Speed DOS XL, including under cartridge, under ROM, and Axlon banked
    memory versions (modified DOS XL by Optimized Systems Software (OSS))
    - TOP DOS version 1.5, by Eclipse Software
    - Software sold separately:
    - Happy Version Archiver/Editor, by Spartan Software of Minnesota, 1984
    - Also marketed by B&C ComputerVisions as: Scan-It!/810 Happy, 1987
    - Fuzzy/Phantom Sector Maker, by CSS, 1986 (Antic 9/86p48)
    - Archiver Enhancement, by Computer Software Services (CSS), 1987
    - Super Archiver/Editor 3.0, The Archiver Tracer

    The Chip, by Spartan Software of Minnesota, 1983-1984
    The Chip with Archiver I, by ICD, 1984
    Scan-It!/Chip, from B&C ComputerVisions, 1987
    - Popularly: "Archiver chip", "810 Archiver", "Archiver/810", "Archiver"
    - Navigate/edit/create nonstandard format disks
    - Shipped with Archiver/Editor program
    - Disassembler, sector editor, custom formatter and mapper
    - Software sold separately:
    - Archiver Enhancement, by Computer Software Services (CSS), 1987
    - Super Archiver/Editor 3.0, The Archiver Tracer

    810 Turbo (810T), by Neanderthal Computer Things (NCT), 1983-1984
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - 1983 units supplied with:
    - N/DOS Generator (SD disk, patches a copy of Atari DOS 2.0S for
    single/double density support and more)
    - NCT 810 Turbo OS Single/Double dens (OS/A+ Version 2, SD disk)
    - NCT 810 Turbo OS Double dens only (OS/A+ Version 4, DD disk)
    - 810T Utilities disk (SD), containing:
    Backemup, Packemup, Revcheck, Reconfigure, Diagnostics
    - 1984 units supplied with Mach DOS (Pre-release name: MACH 2XH DOS)

    Separator, by Percom, 1982
    - Data/clock separator circuit for 1980-1981 810 drives without Atari's
    Data Separator Board
    Right-Write, by Gardner Computing, 1983
    - Write to side 2 of any disk without notching out a hole in the disk
    - Later: Wright-Right or Write-Right by Duplicating Technologies
    DS-810 Disk-Switch, by Computer Software Center (CSC), 1983
    - Write to side 2 of any disk without notching out a hole in the disk
    - Write protection to any disk
    Protector, by Computer Software Services (CSS), for 810/1050/Indus GT, 1983
    - Includes hardware and software
    - Bad sector generator; also move/rearrange data, scramble directories Silencer, by CSS, for 810/1050, 1984
    - Eliminates loud drive sounds when reading bad sectors
    - Write to both sides of any disk without notching disks
    Over-Write [810 version], by Computer Support, 1985
    - Write to side 2 of any disk without notching out a hole in the disk
    Bad Sector, by Computer Support, 1985
    - Write bad sectors to any diskette; can back up some protected disks Electronic Phantom Sector Maker, by CSS, 1987 (Antic 9/87p28)
    - Installs into any drive, no other modification needed
    - Can be combined with other upgrades including Happy and
    The Chip/Archiver
    - Make fuzzy/phantom sectors or fuzz portions of sectors
    - Find/Display valid data, CRC errors and phantom sectors
    - Deluxe version: Allows you to switch between CRC and phantom sectors
    without having to readjust hardware module each time

    ------------------------------

    Subject: 3.2.2) What is the Atari 1050 Disk Drive?

    Portions of this section developed by Laurent Delsarte from the 1050 Field Service Manual.

    The Atari 1050 disk drive was introduced in June 1983 as a replacement for
    the 810 disk drive. The 1050 is fully backward compatible with the 810, with the addition of a new "double density" mode of operation offering 130KiB of data storage per diskette. The "double density" mode works with a standard
    (of its time) 5.25 inch soft-sectored diskette ("floppy disk") which is certified for double density (Modified Frequency Modulation encoding method) use.

    While Atari called the new 1050 mode "double density", the 1050 is not capable of the 180KiB double density standard offered in many third party Atari disk drives. Thus, the 1050's "double density" is usually referred to as "enhanced density" or "dual density."

    Like the 810, the 1050 drive has only one drive head, so it can only read/ write to one side of the disk. Also like the 810, the 1050 ignores the index hold/timing hole, so the reverse side of a disk can be accessed by inserting the disk into the drive upside-down.

    - Connectivity: 2 Atari SIO ports for direct connection to Atari computers
    - Shipped with SIO cable CA014122 (3-foot)

    The front of the 1050 features a Power on/off switch, a Power indicator
    light, and a "Disk busy" indicator light. The rear of the unit includes two SIO ports ("I/O Connectors"), a Power In jack, and Drive Select switches:
    Black & White left: Drive 1
    Black right, White left: Drive 2
    Black & White right: Drive 3
    Black left, White right: Drive 4

    More features/specifications of the 1050 disk drive:
    - 6507 microprocessor (MOS Technology MCS6507 or equivalent) @ 1MHz, C010745
    - ROM, Custom 2732 FC100541
    - 6810 128 x 8 bit static RAM (1KiB) (Motorola MCM6810), C014328
    - 6532 PIA (MOS Technology 6532 RAM-I/O-Timer (RIOT) or equivalent), C010750
    - Western Digital WD2793 Floppy Disk Controller (FDC) @ 1MHz, FC100542
    - Late production units (fall 1985) substituted:
    Western Digital WD2797 FDC, FC100817
    - These units require 1050 ROM Rev L and do not work with earlier 1050
    ROM versions.
    - Media used is the same as for the Atari 810.

    Single Density "Double Density"
    (Read/Write) (Read/Write)
    - Tracks per surface 40 40
    - Tracks per inch 48 TPI 48 TPI
    - Recording density (Track 39, max) 2,878 BPI 5,757 BPI
    - Flux density (Track 39, max) 5,757 FCI 5,757 FCI
    - Encoding method FM MFM
    - Capacity unformatted
    o Per track 3,382 bytes 6,510 bytes
    o Per surface 135,280 bytes 260,400 bytes
    - Capacity formatted
    o Sectors per track 18 26
    o Bytes per sector 128 bytes 128 bytes
    o Bytes per track 2,304 bytes 3,328 bytes
    o Bytes per surface 92,160 bytes 133,120 bytes
    - Transfer rate 125,000 bit/s 250,000 bit/s
    - Read/Write head: 1
    - Write protect sensor: Yes
    - Track 00 sensor: Yes
    - Rotational speed: 288 RPM
    - Rotational speed accuracy: +- 3% (range: 279.36 - 296.64 RPM)
    - Average latency: 110 milliseconds
    - Access time
    o Track to track (max): 40 milliseconds
    o Head settling (max): 30 milliseconds
    o Motor start (max): 1000 milliseconds

    The 1050 drive features a horizontal slot with latch bar door mechanism.
    To complete the insertion of a disk, turn the latch bar clockwise ninety degrees. To release the disk, turn the latch counterclockwise.

    1050 industrial design (case): Tom Palecki

    The 1050 disk drive is used with an external 9 volt AC transformer power
    supply rated for at least 50 watts; Atari CA017964 or equivalent.

    The 1050 was made for Atari in Singapore by Atari-PCI Enterprises Pte. Ltd. from May 1983 to December 1984 (very common), in Hong Kong by Atari-Wong Co. from November 1984 to February 1985 (fairly rare), and again in Singapore by Atari-PCI Enterprises Pte. Ltd. from October 1985 to December 1985 (also
    fairly rare).

    1050 drives made in Singapore use a Tandon drive mechanism, while 1050 drives made in Hong Kong use a World Storage Technology (WST) drive mechanism.

    Several different 1050 ROM (Atari part FC100541) versions have been documented by Atari users, with no practical differences among them. 1983 units shipped with Rev J, 1984 Singapore units shipped with Rev K, 1984-1985 Hong Kong units shipped with an alternate version of Rev K, and 1985 Singapore units shipped with Rev L. See: http://atariage.com/forums/topic/156462-1050-roms/?p=3580891

    1983 production units shipped with DOS 2.0S and in North America only, units produced winter 1984 to winter 1985 shipped (worldwide) with DOS 3, and units produced fall 1985 shipped with DOS 2.5.

    Manuals:
    - Atari 1050 Disk Drive Owner's Guide C061509 (6 pages)
    - Atari 1050 Disk Drive Owner's Guide C024321 (international; 37 pages)
    - Atari DOS 2.5: 1050 Disk Drive Owner's Manual C072033

    Technical manuals: Atari 1050 Disk Drive Field Service Manual FD100330
    - REV. 01 October, 1983
    - REV. 03 October, 1985

    Third-party upgrades for the 1050 (grouped by "family") =================================
    Happy 1050 Enhancement, by Happy Computers, Inc. (Richard Adams), 1984
    - Board includes a 6502 microprocessor and a RAM buffer:
    Up to 36 sectors (SD mode: 2 tracks / 4608 bytes)
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - "Happy" Warp Speed standard high speed reads disks up to 500% times faster
    than standard 1050 with any software; supporting software also supports
    buffered fast write with verify
    - Navigate/edit/create nonstandard format disks
    - Warp Speed Software disk included, contains Warp Speed DOS
    (modified Atari DOS 2.0S), Diagnostic, Sector Copier, Happy Backup, Happy
    Compactor, Multi Drive Happy Backup, Tracer
    - (Rev 2 ROM) ICD US Doubler emulation for UltraSpeed software compatibility
    - IBMXFR IBM Transfer Program included, 1988- (Warp Speed Software v. 7.10)
    - Adds SS-DD "IBM format": 40 tracks, 9 sectors of 512 bytes = 180KiB
    - Software sold separately by Happy Computers:
    - Warp Speed DOS XL, including under cartridge, under ROM, and Axlon
    banked memory versions (modified DOS XL by Optimized Systems Software
    (OSS))
    - TOP DOS version 1.5, by Eclipse Software
    - Software sold separately:
    - Happy Version Archiver/Editor, by Spartan Software of Minnesota, 1984
    - Also marketed by B&C ComputerVisions as: Scan-It!/1050 Happy, 1987
    - Fuzzy/Phantom Sector Maker, by CSS, 1986 (Antic 9/86p48)
    - Archiver Enhancement, by Computer Software Services (CSS), 1987
    - Super Archiver/Editor 3.0 and The Archiver Tracer
    - Happy Doubler, by Innovative Concepts, 1989
    - US Doubler compatible/UltraSpeed capable (software solution)
    - Ability to configure drives as D5: through D8:
    - Hardware upgrades for Happy 1050 Enhancement:
    o Happy 1050 Controller, by Happy Computers, Inc., 1986
    - Hardware switch to select Happy Fast or Slow mode
    - Hardware switch to control write protection, with LED indicator
    - Write to reverse side of disks without punching holes
    o Imitator Controller, by Innovative Concepts, 1987
    - Hardware switch to select Happy Fast or Slow mode
    - 3-position switch for write protect mode:
    1) As normal, 2) Do not write, and 3) Will write to any disk
    - Two-color LED for write-protect status
    o IC Chip, by Innovative Concepts, 1988-11-11
    - US Doubler compatible/UltraSpeed capable (replacement Happy ROM)
    Happy 1050 Maximizer, by Happy Computers, Inc.
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - Happy 1050 Controller upgrade compatible
    - Maximizer to Enhancement Upgrade available from Happy Computers
    High Speed Board 1050, by Irata Verlag, 1985 (West Germany)
    - Happy 1050 Enhancement clone
    1050 Lazer Enhancement, from Utility House (1986) (UK)
    - Happy 1050 Enhancement clone
    - Shipped with The Lazer Drive Supercharger software from Utility House
    1050 IS Plate, by Innovated Software (Robert Perry), 1986
    - Add-on board includes 6502 and 16KiB RAM buffer. Plugs into 6507 socket.
    - Happy 1050 Enhancement compatible/near-clone
    - Emulation of: IS Doubler, US Doubler, standard 1050, Archiver/810
    (UltraSpeed and Archiver software compatible)
    - System supports up to 16 drives
    - Shipped with 2-sided disk including IS Doubler/US Doubler emulation, high
    speed disk copiers (standard and 130XE versions), file loader, custom disk
    formatter (including bad sectors), track tracer
    - Late units: Software instead built-in on ROM
    - Sold separately for use with early units: ISP Gremlin Grabber
    - Most units shipped with Gremlin Grammer II or Gremlin Grabber III
    Klone, by Computer Software Services (CSS), 1986 (USA)
    - Happy 1050 Enhancement clone
    - Happy Warp Speed Software (pre-7.0) included
    Klone II, by Computer Software Services (CSS), 1987 (USA)
    - Happy 1050 Enhancement clone
    - Happy Warp Speed Software (7.0) included
    Copy Card 7.0, by ????, year ???? (Europe)
    - Happy 1050 Enhancement compatible/near-clone
    Hyper Drive, by Chaos! Computers (UK), 1994
    - Happy 1050 Enhancement clone
    - Shipped with software package (Ver. II): Hyper Fast DOS, Hyper Sector
    Copier, Hyper Back-Up System, US Doubler Emulation, HyperCompaction,
    Diagnostic Tester, Archiver/810 Emulation, Multi Drive Back-Up
    - See review & ad, Page 6's New Atari User #75 pp. 30-37, 39

    US Doubler, by ICD, 1984
    - ROM replacement chip and 128 byte RAM chip; some drives require moving two
    jumpers also
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - "UltraSpeed" standard high speed "54K baud" via sector skewing; supporting
    software required for high speed (initially: ICD SpartaDOS)
    - As of 1985, provided with or without the ICD SpartaDOS Construction Set SuperMax, by Super Products
    - US Doubler compatible/UltraSpeed capable
    - Add-on board, switch between standard and replacement drive ROM
    IS Doubler, by Innovated Software (Robert Perry), 1985?
    - US Doubler clone

    Warp Drive, from Stocksoft (UK), 1986
    - Add-on control board replaces two chips
    - Back up including most types of bad sectors
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - Shipped with public domain backup software, double density Menu Maker
    - Archiver/810 compatible (Rev 2 and up)
    Super Archiver, by Computer Software Services (CSS), 1987
    - Add-on board, known as: "Super Archiver Mod", "1050 Super Archiver Chip"
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - Archiver/810 compatible; US Doubler compatible/UltraSpeed capable
    - Navigate/edit/create nonstandard format disks
    - Included software: Super Archiver/Editor 3.0, Super Archiver (skew) 3.1,
    Super Archiver Fuzzy Sector Maker, The Archiver Tracer, Super Archiver
    Diagnostic
    - Also sold without software (B&C ComputerVisions)
    - Bit-Writer upgrade sold separately by CSS (1988):
    - Writes bits rather than sectors, for increased copy capabilities
    Super Archiver II, by CSS, 1988
    - Enhanced density version of CSS Super Archiver
    - Sold complete or as a software-only upgrade for CSS Super Archiver
    - Software: Super Archiver/Editor 3.03 (enhanced density), Super Archiver
    Fuzzy Sector Maker (enhanced density), The Archiver Tracer, Super Archiver
    Diagnostic
    BitWriter 1050 Replica, by Jurgen van Radecke (tfhh), 2016
    - Contains the Super Archiver 1050 and the BitWriter 1050 on one single PCB
    - http://www.van-radecke.de/STUFF/tfhh_HW_info.pdf

    Reproducer, by Gardner Computing, 1984
    - Hardware + software
    - Navigate/edit/create nonstandard format disks
    Density Doubler 1050, by Duplicating Technologies (DT), 1986
    - 6502 microprocessor, 8KiB RAM
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - "High Speed": Whole track buffering (18 sectors, single or double density)
    - ICD US Doubler emulation for UltraSpeed software compatibility
    - Supplied with double density DOS (MachDOS? MYDOS?)
    1050 Duplicator, by Duplicating Technologies (DT), 1986
    - 6502 microprocessor, 8KiB ROM, 8KiM RAM
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - "High Speed": Whole track buffering (18 sectors, single or double density)
    - "Ultra High Speed" software support:
    - Earler versions: 52,000 baud (52,000 bit/s), but not for all 1050 drives
    - Later versions (4+?): Somewhat slower, for all 1050 drives
    - US Doubler compatible/UltraSpeed capable
    - Navigate/edit/create nonstandard format disks (including enhanced density)
    - Supplied with double density DOS (MachDOS? MYDOS?)
    - Sources: http://www.oldcrows.net/~patchell/atari/duplicator.html
    - CheerUp Upgrade, by Happy Computers, Inc., 1987
    - Changes 1050 Duplicator to Happy 1050 Enhancement software compatible

    1050 Turbo, by Bernhard Engl for Gerald Engl Computertechnik, 1985-1988
    - Hardware includes replacement ROM (no microprocessor; no RAM buffer)
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - "Turbodrive" standard high speed 68200 bit/s ("70000 baud") via sector
    skewing; high speed supporting software NOT necessary for high speed,
    instead supporting software is loaded from drive ROM
    - Software on ROM: Backup Machine II, Magic Formatter, Maintenance Box
    - http://www.strotmann.de/~cas/Infothek/1050Turbo/
    - Turbo 1050 Replica, by Jurgen van Radecke (tfhh), 2017
    - http://www.van-radecke.de/STUFF/tfhh_HW_info.pdf
    Top Drive 1050, by Ataserw (1987 or 1988)
    - 1050 Turbo clone (ROM by P.Z. Karen, brand of of LDW)
    - Software: TURBO DOS ("TUR-DOS") disk or cartridge. Known versions:
    - TURBO DOS (c) 1989 ver 2.5 (disk?)
    - TUR DOS - (c) 1990 rev 4.0 (cartridge)
    wszelkie prawa JS & ATASERW Tychy
    - Available upgrade project converts to Happy 1050 Enhancement compatible
    - Details here: http://preview.tinyurl.com/npla4t6

    Speedy 1050 (Mini-Speedy), by Compy-Shop, 1986
    - Includes 65C02 microprocessor, 8KiB RAM buffer, 8KiB program ROM space
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - "Speedy" standard high speed; supporting software required for high speed
    - Speedy 1050N: Internal add-on
    - Speedy 1050NE: External add-on
    - Speedy 1050T: Internal add-on with (external) track display
    - Speedy 1050TE: External add-on with track display
    - Above models: Optional hardware switches for write-protect and
    fast/slow mode control
    - Mini-Speedy S: Internal add-on with 8KiB Sector Copy program in ROM
    - Mini-Speedy D: Internal add-on with 8KiB mini-Bibo-DOS in ROM
    - Mini-Speedy DS: Internal add-on with both Sector Copy and mini-Bibo-DOS
    programs in ROM, hardware switch selectable
    - Super-Speedy prototype: equivalent to Mini-Speedy DS plus track display
    and 192KiB RAM buffer, requiring special software support
    - System disk includes: Speedy Test, Sector Copier. Mini-Speedy system disk
    also includes: Speedy Backup, Speed Init, DiskMapper, HSS Copier
    - Sold separately by Martin Reitershan Computertechnik:
    - Turbo-Speedy DC -- Upgrade replaces mini-Bibo-Dos with the company's
    Turbo-DOS XL/XE, also new firmware; 24KiB ROM space total
    - Modern reproductions by Jurgen van Radecke (tfhh):
    - Mini-Speedy 1050 (2015), Mini-Super-Speedy 1050 (2019)
    - http://www.van-radecke.de/STUFF/tfhh_HW_info.pdf
    Mega Speedy (Guus Assmann & Matthias Reichl, 2014)
    - Out-of-the-box it supports the original 1050, Speedy, Super Speedy,
    a new Mega Speedy, 1050 Turbo and 1050 Duplicator modes.
    - Hardware can also emulate Happy, US Doubler, Super Archiver, and Supermax,
    but you need to provide the ROMs for these upgrades yourself.
    - More info: http://www.realdos.net/MegaSpeedy.html
    - Software and firmware: http://www.horus.com/~hias/megaspeedy/
    - Documentation: http://www.realdos.net/MegaDocs.html

    Tygrys 1050, by Marek Bojarski of Navitron (1988)
    - Version 1.0: US Doubler clone?
    - Version 2.0: US Doubler and 1050 Turbo compatibility?

    TOMS Multi Drive 1050 (1990)
    - Adds single-sided, double density (180KiB) operation (Percom compatible)
    - Adds SS-DD "IBM format": 40 tracks, 9 sectors of 512 bytes = 180KiB
    - Compatibilities: Happy 1050 Enhancement, 1050 Turbo, 1050 Duplicator
    - Software: TOMS Copier, Track Master, Tracer, Get Track, Weak Writer,
    Bad Formatter, Track Writer, IBM DOS, IBM 360, Turbo Drive Kopier

    Other:
    -----
    Protector, by Computer Software Services (CSS), for 810/1050/Indus GT, 1983
    - Includes hardware and software
    - Bad sector generator; also move/rearrange data, scramble directories Silencer, by CSS, for 810/1050, 1984
    - Eliminates loud drive sounds when reading bad sectors
    - Write to both sides of any disk without notching disks
    Over-Write [1050 version], by Computer Support, 1985
    - Write to side 2 of any disk without notching out a hole in the disk
    Bad Sector, by Computer Support, 1985
    - Write bad sectors to any diskette; can back up some protected disks Write-Right or Wright-Right, by Duplicating Technologies, 1986
    - Write to side 2 of any disk without notching out a hole in the disk Electronic Phantom Sector Maker, by CSS, 1987 (Antic 9/87p28)
    - Installs into any drive, no other modification needed
    - Can be combined with other upgrades including Happy 1050 Enhancement,
    Archiver, and Duplicator
    - Make fuzzy/phantom sectors or fuzz portions of sectors
    - Find/Display valid data, CRC errors and phantom sectors
    - Deluxe version: Allows you to switch between CRC and phantom sectors
    without having to readjust hardware module each time
    IC1050 Controller, by Innovative Concepts, 1989
    - 3-position switch for write protect mode:
    1) As normal, 2) Do not write, and 3) Will write to any disk
    - Two-color LED for write-protect status

    ------------------------------

    Subject: 3.2.3) What is the Atari XF551 Disk Drive?

    The Atari XF551 disk drive was introduced in June 1987 as a replacement for
    the 1050 disk drive. The XF551 is fully backward compatible with the 1050, with the addition of two new modes of operation: a true "double density" mode offering 180KiB of data storage per (single-sided) diskette (fully compatible with 3rd party double density drives for the Atari), and a "double-sided
    double density" mode offering 360KiB of data storage per (2-sided) diskette.

    Unlike the 810 or 1050, the XF551 drive has two drive heads, so it can read/write to both sides of a 2-sided floppy disk (in double-sided double density 360KiB disk mode). The 360KiB mode of the XF551 writes "backwards" to the second side of the disk in comparison to the way data would be stored on the reverse side of a disk, inserted into the drive upside-down, in single- sided double density 180KiB mode.

    When working with double-sided double density 360KiB disks, the XF551 is also capable of communicating with the computer at about twice data rate of the earlier Atari 1050 or 810 drives. This XF551 high speed mode is supported by: DOS XE, SpartaDOS X, XDOS, MyPicoDos, Micro-SpartaDOS, SuperDOS, Turbo-DOS, BW-DOS. A patch was also developed for SpartaDOS 3.2d.

    - Connectivity: 2 Atari SIO ports for direct connection to Atari computers
    - Shipped with SIO cable CA014122 (3-foot)

    The front of the XF551 features a "Disk busy" indicator light. (Notably,
    there is no power indicator light on the XF551.) The rear of the unit
    includes a power on/off switch, a Power jack, two SIO ("Peripheral") ports,
    and Drive Select DIP switches:
    Left & Right down: Drive 1
    Left down, Right up: Drive 2
    Left up, Right down: Drive 3
    Left & Right up: Drive 4

    More features/specifications of the XF551 disk drive:
    - Microcontroller. One of:
    - Intel 8040 @ 8.3333MHz, CB101393
    - Intel 8050 @ 8.3333MHz, C070235
    - The 8050 has provision for 4KiB on-board ROM.
    (Early Atari and media reports incorrectly indicated a 6507 microprocessor.)
    (The DOS XE: XF551 manual incorrectly indicates 18.3333MHz.)
    - 4KiB ROM firmware
    - Contained within the 8050 of some units, while other units with the
    8050 and all units with the 8040 use ROM located on a separate chip.
    - Western Digital WD1772 Floppy Disk Controller (FDC) C026028
    - Late production units substituted: Western Digital WD1770
    - SIO Data rate (normal): 19,040 bit/s (NTSC), 18,688 bit/s (PAL)
    (high speed): 38,908 bit/s (NTSC), 38,553 bit/s (PAL)
    - High speed available in DS/DD 360KiB mode operation only
    - Rotation rate: 300 RPM
    - Media used is the same as for the Atari 810.
    - The XF551 has been known to be more likely to destroy fragile, poor-quality
    diskettes in attempt to read them than other disk drives for the Atari.
    This is suggested to be a consequence of the XF551 drive heads pressing
    against the disk media with slightly more force compared to other drives.

    Operating modes Single Dual Double Double
    Encoding Method FM MFM MFM MFM
    Number of sides 1 1 1 2
    Total tracks 40 40 40 80
    Sectors per track 18 26 18 18
    Bytes per sector 128 128 256 256 (total capacity)
    Total Bytes 92,160 133,120 184,320 368,640 (total capacity)

    The XF551 drive features a horizontal slot with latch bar door mechanism.
    To complete the insertion of a disk, turn the latch bar clockwise ninety degrees. To release the disk, turn the latch counterclockwise.

    XF551 drives were manufactured for Atari in two versions, both made in Japan.
    - Mitsumi XF551 (most units)
    - Earlier production; common in North America and Europe.
    - Disk Busy light is rectangular, green, and is located below the
    "straight" drive latch
    - See: http://farm5.static.flickr.com/4052/4669794021_de721aa12d_b.jpg
    - When the drive latch is opened, an inserted disk stays in place until
    removed manually.
    - Inserting a disk does not cause any drive activity.
    - Like the Atari 810 and 1050, the Mitsumi XF551 ignores the disk's index
    hole/timing hole when reading/writing, so the Mitsumi XF551 CAN read
    from, and write to, the reverse side of a disk in single-sided (90KiB,
    130KiB, or 180KiB) mode if the disk is inserted into the drive upside-
    down ("flippy" disk with second index hole/timing hole not needed).
    - Chinon XF551 (Chinon FZ-502 mechanism) (uncommon/rare late production units)
    - Disk Busy light is round, red, and is located directly to the left of the
    "non-straight" drive-latch.
    - http://www.atarimax.com/jindroush.atari.org/data/hardpics/xf551__f.jpg
    - Opening the drive latch causes an inserted disk to be ejected.
    - When a disk is inserted, the drive motor briefly spins and the Disk Busy
    light flashes accordingly.
    - Unlike the Atari 810 and 1050, the Chinon XF551 utilizes the disk's index
    hole/timing hole when reading/writing, so the Chinon XF551 CANNOT read
    from, nor write to, the reverse side of a disk in single-sided (90KiB,
    130KiB, or 180KiB) mode if the disk is inserted into the drive upside-
    down (unless the disk is a "flippy" disk with a second index hole/timing
    hole corresponding to the reverse side).

    Unlike the Atari 810 and 1050, the XF551 (both Mitsumi and Chinon) utilizes
    the disk's index hole/timing hole when formatting the disk. As a result, the XF551 CANNOT format the reverse side of a disk in single-sided (90KiB, 130KiB, or 180KiB) mode if the disk is inserted into the drive upside-down (unless the disk is a "flippy" disk with a second index hole/timing hole corresponding to the reverse side).

    The XF551 disk drive is used with an external 9 volt AC transformer power supply rated for at least 50 watts; Atari CA017964 or equivalent.

    The XF551 shipped with DOS 2.5 (1987-1988) or DOS XE (from 1989).


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