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

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

    Manuals:
    - Atari DOS 2.5: XF551 Disk Drive Owner's Manual C033537
    - Atari DOS XE: XF551 Disk Drive Owner's Manual C300557

    The key engineer/designer of the XF551 was Jose Valdes at Atari.

    Third-party upgrades for the XF551:

    XF35 Kit, by Innovative Concepts, 1988-11-11
    - Developed by Bob Woolley
    - A standard 3.5" 720KiB drive mechanism (not included with Kit) may replace
    the 5.25" drive of the XF551, or it may be added to the drive making it
    possible to select one or the other using a toggle switch.
    - Dual drive option requires several additional parts, not included with Kit
    - Kit also includes replacement drive ROM: (thanks Bob Woolley for details)
    - Changes the number of tracks to 80,
    - Tweaks the track seek timing to match a typical 3.5,
    - Adds (or deletes) spin-up delay that improves write reliability, and
    - Provides for density retry.
    - XF551 high speed remains available

    XF Single Drive Upgrade, by Computer Software Services (CSS), 1991
    -- Replace the 5.25" drive mechanism with a 3.5" drive mechanism
    -- US Doubler compatible/UltraSpeed capable
    -- Can read:
    - 3.5" SS-DD MS-DOS format 360KiB floppy disks
    - 3.5" DS-DD MS-DOS format 720KiB floppy disks
    - Shipped with IBM/ST Transfer Utility disk, containing IBMREAD.COM http://www.nleaudio.com/css/products/XFsingdrup.htm

    XF Dual Drive Upgrade, by Computer Software Services (CSS), 1991
    - Same as XF Single Drive Upgrade, except keep using the XF551 5.25" drive as
    well. Result is two disk drives; the new 3.5" drive assumes the next drive
    number higher than the 5.25" drive. http://www.nleaudio.com/css/products/XFdualdrup.htm

    XF551 Enhancer
    - By Computer Software Services (CSS)
    - Provides a switch that allows the XF551 to read/write/format, in single-
    sided mode, the back side of a disk that has only one index hole/
    timing hole corresponding to the front side of the disk.
    - No need for the disk to have a second write protect hole.
    - A write protect disable is built in.
    - 60Hz version for North America or 50Hz version for Europe http://www.nleaudio.com/css/products/XF551enh.htm

    XF Update
    - By Computer Software Services (CSS), 1992
    - Replacement drive operating system (ROM)
    - "Runs more commercial software"
    - Changes density properly
    - US Doubler compatible/UltraSpeed capable
    - Improved/optimized interleave in high speed formats
    - Can read:
    - 5.25" SS-DD MS-DOS format 180KiB floppy disks
    - 5.25" DS-DD MS-DOS format 360KiB floppy disks
    - Shipped with IBM/ST Transfer Utility disk, containing IBMREAD.COM http://www.nleaudio.com/css/products/XFupdate.htm

    XF Speedy
    - (c) 1994 Klaus Peters Elektronik + Software
    - Converts drive to a Speedy 1050 clone with a DSDD 360KiB mode
    - Replaces the 8040 microcontroller with: a 65C02 microprocessor, ROM, Memory

    Hyper-XF (or HyperXF)
    - (c) 1998 Stefan Dorndorf
    - Replacement drive operating system (ROM)
    - Hyper-XF 1.0A is for original XF551 with 5.25" drive
    - Hyper-XF 1.0B is for the XF551 with replacement 3.5" drive installed
    - US Doubler compatible/UltraSpeed capable
    - "Hyper Speed" is an UltraSpeed support routine in ROM
    - Allows the drive to support UltraSpeed using DOS versions that
    otherwise lack such support
    - XF551 standard high speed is removed
    - Can use disk partitions (2 on 5.25", 4 partitions on 3.5") with mixed
    Densities (S/E/D) or standard 360KiB (5.25") / 720KiB (3.5")
    - Can theoretically read/write ST/PC 720KiB disks (software is missing!)
    - Improved double density detection http://atariage.com/forums/topic/84017-xf551/#entry1023935 (XFTOOLS.ZIP)

    Reimaged XF551 Disk Drive Controller
    - By Bits of the Past (Dropcheck / Lenore Underwood), 2014
    - With Modern Power Supply or with Original Power Supply http://www.bitsofthepast.com/

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

    Subject: 3.2.4) What were the Atari 815, XF521, and XF351 Disk Drives?

    Introduced in June 1980, the Atari 815 Dual Disk Drive featured two single- sided, double density (MFM encoding) disk drives. The 815 would not have a single density (810-compatible) operation mode (a shortcoming that would inspire Percom to invent the "Percom configuration block" which became a standard for density-configurable Atari disk drives).
    - Total storage capacity per diskette:
    40 tracks x 18 sectors/track = 720 sectors/disk
    720 sectors x 256 bytes/sector = 184,320 bytes/disk (180KiB)
    - While most 815 sample drives utilized the same Tandon drive mechanism found
    in late-production Atari 810 drives, there were also 815 sample drives built
    that used the MPI drive mechanism found in earlier 810 drives (including all
    810 drives manufactured while the 815 was under development).
    - Manual: Atari 815 Operator's Manual C016377
    - The 815 disk drive has a built-in power supply (plugs directly into the
    wall, 120V AC).
    - 815 accessories from Atari:
    o CX8201 Master Diskette II
    (DOS II version 2.0D, or DOS 2.0D; version of DOS II supporting both 815
    and 810 disk drives; prototype box exists, but never shipped)
    o CX8202 5 Blank Diskettes. (unformatted; for 810/815 disk drives)
    Minimal production, see: http://www.myatari.com/ebay/815dt.html
    - Atari continued to promote the 815 through the summer of 1981 (see Company
    Store price list for 8-24-81 for a late reference); it was dropped from
    the product line by October 1981. Prototype units exist (according to
    Atarimuseum.com: 60 units were produced), but the 815 never shipped.
    http://www.atarimuseum.com/computers/8BITS/400800/815/815.html

    Previewed in January 1985, the Atari XF521 disk drive was to be a 5.25", 130KiB, XE-styled, feature-equivalent, and gradual replacement for the Atari 1050. The XF521 never shipped, and no more than a handful of prototype units may exist.
    Pictures: http://www.atari-computermuseum.de/pics/zubehoer/xe/xf521.jpeg
    http://www.rhod.fr/ataripics/Xf521_xegs.jpg

    The Atari XF351 disk drive was previewed several times from March 1986 through January 1987. With ADOS (would ship as: DOS XE), the 3.5", single-sided
    double density XF351 was reported to provide 325KiB (6/1986 report) or 320KiB (9/1986 report) of storage (formatted) per disk. The XF351 never shipped, and no more than a handful of prototype units exist.
    Picture: http://www.atari-computermuseum.de/pics/zubehoer/xe/xf351.jpg Discussion: http://atariage.com/forums/topic/231674-xf351-for-sale-on-ebay/

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

    Subject: 3.2.5) What other floppy disk drives were designed for my Atari?

    Major contributors to this section: Glenn M. Saunders, Tomasz M. Tatar,
    James Bradford, Konrad M. Kokoszkiewicz, Don Schoengarth, Andreas
    Koch, TXG/MNX

    This section attempts to comprehensively list released 3rd-party floppy disk drives designed for use with the Atari. These attach to the computer via SIO and generally include two Atari SIO ports, unless stated otherwise. Top transfer rate is 19.2 kbit/s unless stated otherwise. Media requirements, unless stated otherwise, are the same as for the Atari 810.

    LEGEND
    ======
    SD = Single Density, 5.25" floppy disks, 90KiB/side, 810 compatible
    ED = Enhanced Density, 5.25" floppy disks, 130KiB/side, 1050 compatible
    DD = Double Density, 5.25" floppy disks, 180KiB/side, Percom compatible
    SS = Single-Sided
    Drive has only one drive head, so it can only read/write to one side
    of the disk. The reverse side of a disk may or may not be used by
    inserting the disk upside-down, depending on whether the drive uses
    or ignores the index hole/timing hole, and whether the disk is a
    (rare) "flippy" disk with two index holes/timing holes.
    DS = Double-Sided
    The following information is mostly taken from the documentation for
    HiassofT's WriteAtr program, http://www.horus.com/~hias/atari/
    Double-Sided drives for the Atari may use one of three different
    drive-mapping possibilities.
    * Most double-sided Atari disk drives:
    First fill tracks 0-39 (or 0-79) on the first side, then switch
    over to side 2 and again fill tracks 0-39 (0-79 for 3.5" disks).
    * The XF551 first fills track 0 on the first side. Then it
    fills track 1, then track 2, ... up to track 39 (on a 5.25" disk)
    or 79 (on a 3.5" disk). Then it switches to side 2 and fills
    the disk in reverse order (starting at track 39/79, then 38/78,
    ... until it has reached the end of the disk at track 0).
    * The third possibility is the standard in the PC world, but on the
    Atari it's possibly unique to drives connected via the Karin Maxi
    interface.
    If your Atari disk drive uses this mapping, it first fills
    track 0 on side 1, then track 0 on side 2, then seeks to track 1,
    again first fills track 1 / side 1, then track 1 / side 2,
    and so on, until it finishes with track 39 (79) / side 2.
    The drive switches the heads (sides) first before switching
    the track.
    * The TRAK AT-D4 (uniquely?) functions as two logical drives, where
    the second "drive" (side) is read/written in reverse order.

    Amdek AMDC-II SS SD/ED/DD dual drives. Media is 3-inch (3.0")
    Compact Floppy (CF) standard, 180KiB/side,
    shipped with DOS XL
    SN-360 DS SD/ED/DD. 8051 processor, WD2797 controller
    by Atari Studio AS (later, Mirage)
    Astra 1620 SS SD/DD dual drives.
    Shipped with OS/A+ Version 2 or DOS XL
    Astra 2001 SS SD/DD dual drives. Replaced the Astra 1620.
    Shipped with SmartDOS.
    Astra "Big D" DS SD/DD dual drives. Shipped with MYDOS 3.016 (earlier
    units) or Top-DOS 1.5 (later units).
    Astra The "One" DS SD/DD. Shipped with Top-DOS 1.5.
    Astra 1001 SS SD/DD. Shipped with SmartDOS.
    B&C 810 SS SD (B&C ComputerVisions house version of Atari 810) California Access CA-2001 by LDW, 1988 replacement for LDW Super 2000 (Poland)
    SS SD/ED/DD, Indus GT compatible/Synchromesh capable,
    Sold with DOS XL 2.35I1 (manual: "DOS XL 2.35L")
    Upgrades:
    - TOMS Turbo Drive LDW (1989)
    - SS DD IBM:40 tracks * 9 sectors * 512 bytes = 180KiB
    - 1050 Turbo compatible/Turbodrive capable,
    - Synchromesh support removed
    - Software: Turbo Kopier, Track Copier,
    Chaos Initializer, IBM DOS, IBM 360
    - TOMS Multi Drive LDW (1990)
    - Same as TOMS Turbo Drive LDW but also Happy
    Enhancement compatible/Warp Speed capable, and
    1050 Duplicator compatible, and with more software:
    Track Master, Tracer, Index Formatter, Get Track,
    Index Get Track, Bad Formatter, Weak Writer,
    Put Track, Hex Editor
    - Atares Flash system (1991)
    - SS DD IBM:40 tracks * 9 sectors * 512 bytes = 180KiB
    - Unique: 40 tracks * 6 sectors * 1024bytes = 240KiB
    - "Flash Turbo" high speed 127 kbit/s
    - Supplied with FlashDOS
    - SRAMCharger by trub, http://trub.atari8.info/
    - SRAM Charger by Jurgen van Radecke (tfhh), 2018
    http://www.van-radecke.de/STUFF/tfhh_HW_info.pdf Concorde C-221M SS SD/DD; single SIO port - must be at end of SIO
    chain; shipped with DOS XL; see Analog #23 p12.
    Rare pics: https://preview.tinyurl.com/y7uogwos
    Concorde C-222M DS SD/DD see Analog #23 p12, released?
    Flop VD 40 F same as Viatronic VD 40 described below but with standard
    Atari SIO ports. http://preview.tinyurl.com/m3mhqp3 Floppy 2000 by Klaus Peters Elektronik & Software
    DS SD/ED/DD Speedy 1050 clone with a DSDD 360KiB mode,
    Copy 2000 program in ROM
    Indus GT by Indus Systems, Inc., 1983-1986
    by Future Systems, Inc., 1986-1987
    SS SD/ED/DD, Z-80A microprocessor, early units shipped
    with OSS DOS XL 2.20 or 2.30, most units shipped with
    Synchromesh (DOS XL 2.35I1 implementing 38400 bit/s).
    Except early units, shipped with "GT DrivingSystem":
    - GT Estate Wordprocessor, (c) 1983 Elcomp Publishing
    author: H. C. Wagner for IJG, Inc.
    - GT Albert E. Spreadsheet by SIM Computer Products Inc.
    (c) 1982-1983 by David H. Hewit
    - GT Data Manager, (c) 1984 Vervan Software
    authors: Carl M. Evans and Richard M. Leonard
    1986-1987 units (from Future Systems) shipped with
    Synchromesh II (DOS XL 2.35I2 implementing 68200 bit/s)
    and the "GT DrivingSystem" and also:
    - GT Speller for GT Estate Word Processor
    - RAM130 RAM drive for 130XE banked memory
    - INITSYNC.COM - enables Synchromesh during boot up
    Upgrades released by Future Systems in 1986:
    - RAM Charger: 64KiB RAM + Synchromesh II + one of:
    - CP/M 2.2 (including CP/M BIOS) + CP/M Terminal, OR
    - CP/M BIOS (without CP/M 2.2) + CP/M Terminal
    - Synchromesh II (for earlier Indus GT customers)
    Third-party upgrades:
    - CSS Protector: Bad sector generator
    - SRAMCharger by trub, http://trub.atari8.info/
    - SRAM Charger by Jurgen van Radecke (tfhh), 2018
    http://www.van-radecke.de/STUFF/tfhh_HW_info.pdf
    LDW Super 2000 by Logical Design Works, Inc., shipped 12/1987 (Poland)
    SS SD/ED/DD, replaced with CA-2001 in 1988
    Indus GT compatible/Synchromesh capable.
    Sold with DOS XL 3.25I1 (manual: "DOS XL 2.35L")
    Upgrades:
    - TOMS Turbo Drive LDW (or just "TOMS Turbo Drive"),
    described at CA-2001 above
    - TOMS Multi Drive LDW, described at CA-2001 above
    - Atares Flash system (1991) described at CA-2001 above
    - SRAMCharger by trub, http://trub.atari8.info/
    - SRAM Charger by Jurgen van Radecke (tfhh), 2018
    http://www.van-radecke.de/STUFF/tfhh_HW_info.pdf
    Micro MainFrame MF-1681 SS SD/DD, hard/software selectable SD/DD operation,
    high speed backup & data transfer, Z-80 microprocessor
    w/16KiB RAM, hard disk interfacing firmware.
    Shipped with MMF's Maxi-Dos A (Atari DOS 2.0S modified)
    - MF-1682 is MF-1681 + internal add-on 5.25" drive
    - MF-EB1 expansion box: 64KiB RAM for CP/M or OASIS Percom RFD-40S1 SS SD/DD, introduced March 1982; first 810 alternative.
    Early units shipped with "BLD" utility to build Percom
    DOS 2.0P (double density support) from a copy of Atari
    DOS 2.0S; later/most units shipped with OS/A+ Version 4.
    Later units marked: RDF40-S1. Review: InfoWorld 7/26/82 Percom RFD-44S1 DS SD/DD, introduced March 1982.
    Early units shipped with "BLD" utility to build Percom
    DOS 2.0P (double density support) from a copy of Atari
    DOS 2.0S; later/most units shipped with OS/A+ Version 4. Percom RFD-40S2 SS SD/DD dual drives (1983) shipped with OS/A+ Version 4.
    Later units marked: RFD40-S2 (Antic v2n1 review, 4/83) Percom RFD 44-S2 DS SD/DD dual drives (1983) shipped with OS/A+ Version 4. Percom AT88-S1 SS SD, shipped with OS/A+ Version 2. (IW 11/29/82)
    Widely known as: AT-88 (see also Antic v2n8 review)
    Upgrade: Percom Doubler (double density) for the AT-88
    - Percom Doubler supplied with OS/A+ Version 4
    Percom AT88-S2 SS SD dual drives, shipped with OS/A+ Version 2.
    Percom AT88-S1PD SS SD/DD, shipped with OS/A+ Version 4 (fall 1983).
    Full-height drive mechanism (like earlier Percom drives) Percom AT88-SPD SS SD/DD (1984) same as AT88-S1PD but with half-height
    drives (which were sporadically used in earlier Percom
    drives as well)
    Rana 1000 SS SD/DD, standalone disk formatting,
    shipped with SmartDOS
    RCP 810 SS SD (Computer Palace house version of Atari 810)
    SBG D.8002 HS DS SD/ED/DD ICD US Doubler compatible/UltraSpeed capable
    see: http://atariki.krap.pl/index.php/D.8002_HS
    Special Edition SS SD (San Jose Computer house version of Atari 810) Spider SS SD/ED/DD. XF551 clone, 70 units made. See:
    http://www.atariage.com/forums/index.php?showtopic=99716 TOMS 720 DS SD/ED/DD/QD/iD/ID/CD. 1991.
    DS-DD 360KiB format is XF551 compatible. Unique formats:
    DS-QD - 2x80 tracks of 18 sectors of 256 bytes = 720KiB
    SS-iD IBM - 40 tracks of 9 sectors of 512 bytes = 180KiB
    DS-ID IBM-2x40 tracks of 9 sectors of 512 bytes = 360KiB
    DS-CD ST -2x80 tracks of 9 sectors of 512 bytes = 720KiB
    Intel 8085 microprocessor, US Doubler compatible/
    UltraSpeed capable, 1050 Turbo compatible/Turbodrive
    capable; MYDOS 4.50, IBMST (for IBM/ST formats) and other
    utilities on ROM; 800.com supplied on disk for PC (for
    accessing ST format 720KiB disks with 1200KiB HD drive) TOMS 720C Same as TOMS 720 but with printer port
    TOMS 720CR Same as TOMS 720 but with printer port and RS-232 port TOMS 710 DS SD/ED/DD/QD. 1994.
    DS-DD 360KiB format is XF551 compatible. Other format:
    DS-QD 2x80 tracks of 18 sectors of 256 bytes = 720KiB
    8080 microprocessor, US Doubler compatible/UltraSpeed
    capable, 1050 Turbo compatible/Turbodrive capable;
    TOMS Navigator and other utilities on ROM
    TOMS 360 DS SD/ED/DD. 1996.
    DS-DD 360KiB format is XF551 compatible.
    US Doubler compatible/UltraSpeed capable,
    1050 Turbo compatible/Turbodrive capable;
    TOMS Navigator and other utilities on ROM
    Trak AT-1 SS SD/DD, shipped with "DDINIT" utility to modify Atari
    DOS 2.0S for double density.
    Trak AT-D1 SS SD. Upgrade: Double density.
    Trak AT-D2 SS SD/DD, shipped with "DDINIT" utility to modify Atari
    DOS 2.0S for double density.
    Trak AT-D4 DS SD/DD, shipped with "DDINIT" utility to modify Atari
    DOS 2.0S for double density. Double-sided operation:
    side 1 is accessed as D1: and side 2 is accessed as D2:. Viatronic VD 40 DS SS/ED/DD XF551 compatible including high speed, 8085
    microprocessor, 8KiB RAM, 8KiB ROM, 300 RPM, WD2797A-PL
    controller, two ports with SIO signals require adapters
    to SIO. http://preview.tinyurl.com/m7sfjwr
    XFD601 (Jacek Zuk) DS SD/ED/DD, US Doubler compatible/UltraSpeed capable,
    Indus GT compatible/Synchromesh capable, 1050 Turbo
    compatible/Turbodrive capable, disk rotation = 360 RPM
    http://atariki.krap.pl/index.php/XFD601
    XFD602 (Jacek Zuk) DS SD/ED/DD dual drives, each same as XFD601
    http://atariki.krap.pl/index.php/XFD602

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

    Subject: 3.2.6) What is the Percom configuration block?

    Sources:
    - MYDOS 4.3A User Guide, page 28
    - Compute! magazine #65, October 1985, page 110-111,
    http://www.atarimagazines.com/compute/issue65/insight_atari.php

    Percom and Percom compatible disk drives for the Atari computer maintain, in memory within the drive, information about the drive's current configuration, and the drive can provide that information to the Atari computer on demand.
    The drive may also allow for the computer to dynamically change one or more configurable options.

    The configuration information consists of a block of 12 bytes. A drive's configuration block may be read by passing "N" ($4E) to it as an SIO command.
    A new configuration block may be written to a drive with an "O" ($4F) SIO command. The "N" and "O" commands closely parallel the "R" and "W" sector input/output commands, except the data length is always 12 bytes, and no
    sector number is needed. The 12 bytes were defined by Percom as follows:

    byte 0: Tracks per side (40 for a standard disk drive)
    byte 1: Disk Drive Step Rate (as defined by Western Digital)
    byte 2: Sectors/Track -- high byte (usually 0)
    byte 3: Sectors/Track -- low byte (18 for standard diskettes)
    byte 4: Side Code (0=single-sided, 1=double-sided)
    byte 5: Disk Type Code --
    bit 2: 0=single density (FM), 1=double density (MFM)
    bit 1: 0=5.25" diskette, 1=8" diskette drive
    byte 6: High byte of Bytes/Sector (0 for Atari 810 compatible)
    byte 7: Low byte of Bytes/Sector (128 for Atari 810)
    byte 8: Translation control
    bit 7: 1=40 track disk I/O on an 80 track drive
    bit 6: Always 1 (to indicate drive present)
    bit 1: 1=Handle sectors 1, 2, and 3 as full size sectors
    bit 0: 1=Sectors number 0-17 (for example) not 1-18
    bytes 9-11 Reserved

    The Percom configuration block standard had the particular importance of allowing for Atari disk drives capable of either single or double density operations, and thus for Atari users with Percom compatible drives to use single or double density disks interchangeably.

    The extent of support for the full standard varies widely among disk drives designed for the Atari. Atari's own 810 and 1050 drives do not support the configuration block at all, while the Atari XF551 and most 3rd party drives
    for the Atari support at least portions of the Percom standard. For example, the Indus GT supports bytes 5-7 only.

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

    Subject: 3.2.7) How can I use an industry standard floppy disk drive?

    The standard interface between floppy disk drive (FDD) and controller was established by the Shugart Associates SA400 minifloppy Disk Drive (1976). The interface normally consists of a 34 conductor ribbon cable, using 34 pin PCB edge connectors (5.25" drive convention) and/or 34 pin header (2x17)
    connectors (3.5" drive convention).

    (Earlier 8" floppy disk drives normally used a 50 conductor ribbon cable and corresponding pin header or PCB edge connectors.)

    This section should list all devices for the Atari computer that provide a standard FDD interface for the system, allowing the addition of one or more standard 5.25" or 3.5" floppy disk drives.

    Unless stated otherwise, these FDD interfaces support single or double density drives, but not high density 1440KiB 3.5" or 1200KiB 5.25" drives.

    Atari disk drives that also add a standard FDD interface --------------------------------------------------------
    - Amdek: AMDC-II (34 pin header)
    - Concorde C-221M (34 pin PCB edge)
    - Matching add-on drives:
    Concorde C-221S (single-sided; released?)
    Concorde C-222S (double-sided; released?)
    - Micro MainFrame MF-1681 (34 pin PCB edge)
    - Percom: RFD-40S1, RFD-44S1, (34 pin header)
    RFD-40S2 (early units)
    RFD40-S2 (later units), RFD 44-S2, (34 pin PCB edge)
    AT88-S1, AT88-S2,
    AT88-S1PD, AT88-S2PD, AT88-SPD
    - Matching add-on drives:
    Percom RFD40-A1 (single-sided)
    AT88-A1 (single-sided) (34 pin PCB edge)
    - Trak: AT-1, AT-D1, AT-D2, AT-D4 (34 pin PCB edge)
    - Matching add-on drive:
    Trak AT-S1 (single-sided)

    Other Atari FDD Interfaces
    --------------------------
    L.E. Systems disk drive (1982)
    - Developer: two partners, including David Small
    - Originally: "Leading Edge Systems"
    - Device is a personality board (oversized) for the 800
    - Board provides two 34 pin connectors for 5.25" floppy disk drives
    - Each connector supports one master and up to three slave drives, for a
    total system potential of 8 disk drives.
    - Drives may be single or double density
    - High speed disk duplication: 17-22 seconds per diskette, up to 7 copies
    at a time (8 drive system)
    - Duplicate Atari disks including non-standard formats and copy protection
    - Can create disks with copy protection. Supports: Bad sectoring, custom
    track layout, deleted sector marks, complete track dumps
    - Originally marketed as an 8 drive system (LEFDC-08) or a 4 drive system
    (LEFDC-04), later a 2 drive system (LEFDC-02) and a single drive system
    were offered as well. Sold with Tandon disk drives.
    - Ads: Antic v1n3 Aug82 p43 and v1n5 Dec/Jan83 p94

    ATR8000, by Software Publishers / SWP Microcomputer Products (1982-1986)
    - 16KiB or 64KiB RAM versions
    - 16KiB units upgradeable to 64KiB RAM
    - 64KiB units supplied with CP/M 2.2 (5.25" disk or 8" disk)
    - Connects to the Atari via SIO (includes 2nd SIO port)
    - 4MHz Z-80A microprocessor
    - RS-232 port (26 pin PCB edge) for modem or serial printer (or standard
    RS-232 terminal in place of an Atari computer)
    - Does not use standard Atari 850 R: device handlers
    - Drive connector: 34 pin PCB edge
    - Attach up to 4 standard floppy disk drives, any combination of:
    5.25" or 8"; single, double or quad density; single or double-sided
    - Unit RAM can be used as a disk buffer
    - 16KiB version: Double density CP/M 2.2 available with 64KiB Upgrade
    - Sold separately by SWP for 64KiB units only:
    - CP/M 2.2 (double density) with ATR8000 CP/M Supplement
    (5.25" or 8" disk versions; 5.25" version supplied with 64KiB units)
    - Supplied with Auto-Term terminal emulator for the Atari (80 column
    display supported via 40 column movable window)
    - Some units also supplied with the autobit3 version of Auto-Term
    for the Bit 3 Full-View 80
    - CO-POWER-88 (internal upgrade): 5.33MHz 8088 microprocessor, 128KiB or
    256KiB, MS-DOS 2.11 (5.25" disks or 8" disks)
    - CO-POWER-Plus (internal upgrade): 5.33MHz 8088 microprocessor, 256KiB
    (expandable in increments of 256KiB to 1MiB) or 1MiB, MS-DOS 2.11
    - CP/M-86 (5.25" disks or 8" disks) for CO-POWER-88 or CO-POWER-Plus
    - Sold separately by SWP:
    - OSS OS/A+ Version 4 (1982-1983) or MYDOS 3.0x/3.1x (1983-1986)
    (5.25" or 8" disk)
    - Autoterm80 (80 column version of Auto-Term for any Atari with high
    resolution monitor)

    HDI High-density Disk Interface, by Erhard Puetz (1990/1991?)
    - A printed circuit board, includes 65C02 microprocessor and WD37C65C
    controller
    - Connect up to 4 standard PC floppy drives
    - Drive types: 5.25" 360KiB, 3.5" 720KiB, 3.5" 1440KiB (any combination)
    - Drive connector: 34 pin header
    - Drives must support the Disk Change signal at pin 34 of the Shugart bus
    - Connects to the Atari via SIO (must be at end of SIO chain)
    - Happy compatible/Warp Speed capable
    - Maximum transfer rate: 500 kbit/s (1440KiB 3.5" disks)
    - See: http://www.atari-central.de/floppyservice/floppy/gb/hdi.htm
    http://atariage.com/forums/topic/158701-hid-disk-interface/

    Floppy Board by Computer Software Services (CSS, 1992)
    - Enables floppy drive port (34 pin PCB edge) of the CSS Black Box
    (which connects to the Atari XL/XE via PBI or Cartridge+ECI
    - Drive types: 5.25" 360KiB, 3.5" 720KiB, 5.25" 1200KiB, 3.5" 1440KiB
    - Reads/writes 5.25" and 3.5" MS-DOS disks, BBXFER software utility included
    - Built-in Black Box Enhancer (Task Master program) and Archiver programs
    - See: http://www.nleaudio.com/css/products/floppy.htm

    Karin Maxi Disk Drive by Mariusz Geisler for Karin (1995?)
    - Parallel device, connects to Cartridge+ECI
    - Design errors result in conflicts with other parallel device peripherals
    - Drive connector: 34 pin PCB edge
    - FDC: WD1770 or WD1772
    - Usual drive types: 5.25" or 3.5", each either 40 tracks or 80 tracks
    - Double-sided formats use PC-standard 'head-first' mapping
    - See: http://blog.3b2.sk/igi/post/ATARI-floppy-disk-drive-KARIN-MAXI.aspx
    http://atariki.krap.pl/index.php/Karin_Maxi

    Karin Maxi Disk Drive 2012, by stryker/trub/drac030/candle
    - Original Karin Maxi design with original design errors fixed
    - See: http://karinmaxidrive.pigwa.net/

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

    Subject: 3.3.1) What is the Corvus disk system?

    For mass storage capacity beyond that of floppy disk drives, microcomputer users of the time of the Atari could turn to drives that utilized a "fixed" or "sealed" magnetic disk. Such devices were still widely known in the early 1980s as "Winchester" disks, after the code name for IBM's influential 3340 Direct Access Storage Facility (14"; 70MB or 140MB) introduced back in 1973.
    As they became much more common by the mid 1980s, the Winchester term mostly disappeared from common usage, along with the alternatives "fixed-disk" and "sealed disk", all ultimately replaced by today's: "hard disk drive"

    One feature of early hard disk drives was that the disk controller was usually a separate component from the disk itself. In the late 1970s and early 1980s several different interface standards for communications between computer
    host, controller, and disk competed for market acceptance. This complicated market landscape, combined with the extreme costs involved, severely limited the sales of hard disks for early home computers.

    Corvus Systems teamed with disk-maker International Memories Inc. (IMI) to develop and market complete, integrated Winchester disk systems compatible
    with many computer platforms, including the Atari 800. It was the first and remained the only hard disk drive solution available for an Atari computer for several years.

    Corvus Systems Atari 800 Disk System (1982) includes:
    - Corvus Winchester Disk Drive unit, one of:
    - Corvus B-Series 5.25" 6MB
    (IMI 5007 disk with IMI 5000 Phase III controller)
    - Corvus B-Series 8" 11MB
    (IMI 7710 disk with embedded controller)
    - Corvus B-Series 8" 20MB
    (IMI 7720 disk with embedded controller)
    - Corvus H-Series 5.25" 6MB (Model 6)
    (IMI 5006H disk with IMI 5000H controller)
    - Corvus H-Series 5.25" 12MB (Model 11)

    [continued in next message]

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