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Atari SH204

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Atari SH204
An SH204 (Blake Patterson, CC BY 2.0)
Manufacturer Atari Corporation; built by Atari Taiwan Manufacturing Corp.[1]
Type 20 MB external hard disk drive
Release date 26 May 1986 (United States)[1]
Discontinued Autumn 1988[1]
Price US$799 (May 1986)[1]
Interface Atari DMA (ACSI) hard disk port[2]
Compatible Atari 520ST, Atari 1040ST and the other ST models with TOS in ROM[3][1]
Dimensions 3.1 × 7 × 15 in (80 × 178 × 380 mm), H × W × D[4]
Weight 4.7 kg[1]
Successor Atari SH205
Power 120 V 60 Hz; 70 W peak, 35 W typical (US specification)[4]
Storage 20 MB (MFM), 612 cylinders, 17 sectors per track[4]

The Atari SH204 is Atari Corporation's first hard disk drive for the Atari ST, a 20-megabyte unit sold from 1986 to 1988. Its grey metal case holds a hard disk, a controller, an interface board and a power supply, and it connects to the ST's DMA hard disk port.[2][1] It was replaced by the Atari SH205, also sold as the Megafile 20.[5][1]

The drive contains a mains power supply. Unplug it before removing the cover.[6]

History

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atari-computermuseum.de records that Atari had planned a 10 MB drive for the ST's launch, the SH104 (announced as the SH317), and a 15 MB model. Neither appeared; the SH104 was withdrawn in autumn 1985 in favour of a 20 MB drive. The SH204 was announced at the Winter CES in January 1986, shown at CeBIT in March 1986 under the name SH324 and at the Spring COMDEX in April as the SH204, and went on sale in the United States on 26 May 1986 at US$799. It was made until autumn 1988. Shortly before then Shiraz Shivji announced at the Atari fair in Düsseldorf that only the SH205 would be delivered from then on.[1] ST-Log reported in January 1989 that the Megafile 20 had replaced the discontinued SH204.[5]

The museum notes that the SH204's rectangular case had to stand beside the computer, while the SH205 could sit under a monitor or a Mega ST.[7][1]

Specifications

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SH204 specifications (Atari C026320 Rev. B, 1986)[4]
Item Value
Capacity 20 MB (MFM)
Geometry 612 cylinders, 2448 tracks, 17 sectors per track
Track density 600 tracks per inch
Data transfer rate 5 Mbit/s
Head positioning Stepper motor
Power supply 120 V 60 Hz
Power consumption 70 W peak, 35 W typical
Dimensions (H × W × D) 3.1 × 7 × 15 in (80 × 178 × 380 mm)
Shock and vibration 10 g operating; 40 g idle, storage or transport
Temperature 5 to 35 °C operating or idle; −30 to 65 °C storage and transport
Relative humidity 20 to 80 % operating or idle; up to 95 % storage or transport (non-condensing)

2448 tracks on 612 cylinders means four heads. atari-computermuseum.de gives the size as 18 × 8.5 × 38 cm and the weight as 4.7 kg.[1] A European SH204 photographed by the museum carries the label "Line voltage range 190-270VAC 50Hz" and a 250 V T1.6A fuse.[8]

Hardware

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Atari's manual describes the controller as two parts: an Atari Hard Disk Interface host adapter, and an intelligent SCSI (ANSI X3T9.2) controller for ST506/412 drives. The host takes commands as six-byte command descriptor blocks.[9]

  • The host adapter card sits at the back of the unit. Atari (Japan)'s schematic for it is drawing C026198 (P/N CA026199), marked "Used on SH204"; it has a PAL16L8, the DMA side, a 50-pin connector to the controller and a three-way DIP switch that sets the unit number.[10][6] The card in the museum's drive is marked "Host Adapter Card C026266 Rev. C".[11]
  • The controller board in the museum's SH204 carries Adaptec AIC-300 and AIC-010 controller chips.[12]
  • The drive is a 5.25-inch MFM mechanism, cooled by a fan at the back of the case.[13][14]

A member of the exxos forum described the arrangement in 2019 as an ACSI-to-SCSI converter in front of a SCSI-to-ST506 controller, where the later SH drives and the Megafiles use a single ACSI-to-ST506 controller.[15] The SH205 schematic shows one board carrying both the host interface and Adaptec AIC-300 and AIC-010 chips.[16]

Setting up

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  • The drive comes with a power cable, a DMA interface cable and the SH Boot Disk. Atari's manual says the interface cable must be no longer than 18 inches.[17]
  • Switch the drive on before the computer. It seeks and calibrates for about 15 seconds, gives a few beeps, and the busy light goes out; then switch on the computer.[18]
  • Booting from floppy, the working boot disk needs AHDI.PRG in its AUTO folder. The SH204 needs an ST with TOS in ROM.[18][3]
  • HDX, Atari's formatting program, lists the SH204 and the SH104 as disk types, and partitions the SH204 into logical drives of 4, 6 and 10 MB.[19]
  • Before moving the drive, run SHIP.PRG from a floppy to park the heads, then switch the drive off.[20]

Unit number

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Atari's SH manual describes a three-way DIP switch on the small board at the back of the unit, with switches weighted 4, 2 and 1, which set the drive's unit number from 0 to 7; all three are ON (unit 0) from the factory.[6] The SH204 has one DMA port and no "Hard Disk Out" port, and Atari's Megafile manual says that an SH204 on the same chain as a Megafile must be the last drive.[8][21] atari-computermuseum.de says the SH204 works only at DMA address 0 because its internal SCSI controller cannot have its DMA ID changed.[1] The two sources disagree; check the switch setting on your own drive.

Repair

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See Atari SH204 General Maintenance for care, the cover screws, the fuse and head parking, and Atari SH204 Troubleshooting Guide for Atari's checks and the controller's error codes. For the drive mechanism itself, see Hard Drive Maintenance and Repair.

Documentation

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  • Atari SH204 Documentation: the SH Hard Disk Drive Owner's Manual (C026263 Rev. B, 1986), the SH204 specification sheet (C026320 Rev. B) and the host adapter card schematic (C026198).
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  • Inside an SH204 (atari-computermuseum.de)
    Inside an SH204 (atari-computermuseum.de)
  • Rear panel of a European SH204 (atari-computermuseum.de)
    Rear panel of a European SH204 (atari-computermuseum.de)
  • Host adapter card C026266 Rev. C (atari-computermuseum.de)
    Host adapter card C026266 Rev. C (atari-computermuseum.de)
  • Disk controller board (atari-computermuseum.de)
    Disk controller board (atari-computermuseum.de)
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References

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  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 "Atari SH104 / SH317", "Atari SH204 Hard Disk Drive" and "Atari SH205 / MEGAFILE 20", in "Atari ST-Peripheriegeräte", atari-computermuseum.de, https://www.atari-computermuseum.de/st_peri.htm#sh204. Secondary source for the maker, factory code, names, showings, sales date, price, end of production, case, size, weight and the DMA address.
  2. ↑ 2.0 2.1 Atari Corp., SH Hard Disk Drive Owner's Manual, C026263 Rev. B, 1986, Introduction, p. 1 (PDF p. 7). File:Atari SH Hard Disk Drive Owner's Manual C026263 Rev B.pdf.
  3. ↑ 3.0 3.1 SH Hard Disk Drive Owner's Manual, chapter 2, Notes and Warnings, p. 18 (PDF p. 24).
  4. ↑ 4.0 4.1 4.2 4.3 Atari Corp., SH204 Hard Disk Drive Specifications, C026320 Rev. B, 1986. File:Atari SH204 Hard Disk Drive Specifications C026320 Rev B.pdf.
  5. ↑ 5.0 5.1 "ST News: Megafile 20", ST-Log issue 27, January 1989, p. 9. https://www.atarimagazines.com/st-log/issue27/109_3_ST_NEWS_MEGAFILE_20.php
  6. ↑ 6.0 6.1 6.2 SH Hard Disk Drive Owner's Manual, chapter 3, Setting the DIP Switches, pp. 19-21 (PDF pp. 25-27).
  7. ↑ "Atari SH205 / MEGAFILE 20 / MEGAFILE 40 Hard Disk Drive", atari-computermuseum.de, https://www.atari-computermuseum.de/st_peri.htm#sh205. Secondary source.
  8. ↑ 8.0 8.1 Photograph of the rear panel of an SH204, atari-computermuseum.de. File:Atari SH204 rear panel (Atari Computermuseum).jpg.
  9. ↑ SH Hard Disk Drive Owner's Manual, appendix B, SH Hard Disk Drive Controller Command Summary, p. 25 (PDF p. 31).
  10. ↑ Atari (Japan) Corporation, Host Adapter Card Schematic Diagram, drawing C026198, P/N CA026199, used on SH204. File:Atari SH204 Host Adapter Card Schematic C026198.pdf.
  11. ↑ Photograph of the SH204 host adapter card, atari-computermuseum.de. File:Atari SH204 host adapter card (Atari Computermuseum).jpg.
  12. ↑ Photograph of the SH204 disk controller board, atari-computermuseum.de. File:Atari SH204 disk controller board (Atari Computermuseum).jpg.
  13. ↑ Photograph of the inside of an SH204, atari-computermuseum.de. File:Atari SH204 interior (Atari Computermuseum).jpg.
  14. ↑ SH Hard Disk Drive Owner's Manual, appendix A, Troubleshooting, p. 23 (PDF p. 29).
  15. ↑ "Just got a new SH204 minus the hard drive", exxos's Atari, Amiga & retro forum, January 2019, post by tzok of 9 January 2019. https://www.exxosforum.co.uk/forum/viewtopic.php?t=1533. Community report.
  16. ↑ Atari (Japan) Corporation, Schematic Diagram (SH205), drawing C100171, sheet 1 of 2. File:Atari SH205 Schematic C100171 sheet 1.pdf.
  17. ↑ SH Hard Disk Drive Owner's Manual, chapter 1, Unpacking and Connecting the Drive, pp. 3-4 (PDF pp. 9-10).
  18. ↑ 18.0 18.1 SH Hard Disk Drive Owner's Manual, chapter 1, Booting the Hard Disk Drive, pp. 6-7 (PDF pp. 12-13).
  19. ↑ SH Hard Disk Drive Owner's Manual, chapter 2, Formatting the Hard Disk, pp. 11-12 (PDF pp. 17-18).
  20. ↑ SH Hard Disk Drive Owner's Manual, chapter 2, Running SHIP.PRG, p. 17 (PDF p. 23).
  21. ↑ Atari Corporation, MEGAFILE Hard Disk Drive Owner's Manual, C300459-001 Rev. B, 1988, chapter 1, Connecting Additional Hard Disk Drives, PDF p. 10. File:Atari Megafile Owner's Manual C300459-001 Rev B.pdf.


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