SCSI2SD

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Revision as of 04:05, 18 May 2014 by Michael (talk | contribs) (v3.4 update)
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The SCSI Hard Drive Emulator for retro computing.

SCSI2SD_V3.0_small.jpg SCSI2SD_V3.0_plain_small.jpg

News

[18 May 2014] v3.4 firmware released.

  • Bug fix for non-512 byte sectors.
  • New scsi2sd-debug log capture utility
  • Windows users upgrading from previous releases MUST delete old USB device information before scsi2sd-config will work again. The USBDeview utility may be used to remove Vendor 04B4, Product 1337.

[16 April 2014] v3.3 firmware released.

  • Many critical bugs are fixed. All SCSI2SD users are urged to upgrade to this version.
  • Better compatibility with older SCSI-1 controllers.
  • Non-standard sector sizes between 64 and 2048 bytes are now supported.

[16 Feb 2014] v3.2 firmware released. This is an important bugfix release. All SCSI2SD users are urged to upgrade to this version.

[02 Feb 2014] I've created the SCSI2SD FAQ to answer some common questions. I am currently working on resolving compatibility issues with some samplers, adding configurable sector-sizes, and creating a smaller 2.5" version to suit old Powerbooks.

[17 Jan 2014] Sign up for the SCSI2SD mailing lists for firmware update notifications.

[27 Dec 2013] v3.1 firmware released.

  • Fix for reading the last sector of the SD card.
  • Performance improvements. 2.5x read, 2x write performance.

[9 Dec 2013] v3.0.1 firmware released.

Overview

Traditional hard drives last 5 years*. Maybe, if you're luckly, you'll get 10 years of service from a particular drive. The lubricants wear out, the spindles rust. SCSI2SD is a modern replacement for failed drives. It allows the use of vintage computer hardware long after their mechanical drives fail. The use of SD memory cards solves the problem of transferring data between the vintage computer and a modern PC (who still has access to a working floppy drive ?)

*All statistics are made up.

Purchase

I am actively building and selling SCSI2SD devices.

Buy Now!

Features

  1. In-built active terminator.
  2. Can optional supply terminator power back to the SCSI bus
  3. Emulates a non-removable hard drive for maximum compatibility.
  4. Supports sector sizes from 64 bytes to 2048 bytes
  5. Firmware updatable over USB
  6. Highly configurable over USB
    • Selectable SCSI ID
    • Selectable parity support
    • Enable/disable Unit Attention Condition
    • Artificial limits on the SCSI disk size (eg. limit size to 4G to avoid OS bugs)
    • Sector size (can also be set via the SCSI MODE SELECT command, as sent by SCSI format utilities).

Technical Specifications

SCSI Interface SCSI-2 Narrow 8-bit 50-pin connector. Supports asynchronous transfers only.
SD Card Interface Standard SDSC (1GB maximum size)

SDHC (32GB maximum size)
SDXC cards are untested. Donations welcome.
Communication is via the SPI protocol at 25MHz.

Power 5V via standard molex drive connector.
Dimensions 10cm x 10cm x 1.5cm

A 3D-printable bracket is available to mount in a standard 3.5" hard disk bay.

Performance

As currently implemented:

Sequential read: 930kb/sec Sequential write: 900kb/sec

Tested with a 16GB class 10 SD card, via the commands:

# WRITE TEST
sudo dd bs=8192 count=100 if=/dev/zero of=/dev/sdX oflag=dsync
# READ TEST
sudo dd bs=8192 count=100 if=/dev/sdX of=/dev/null

For comparison, here are some benchmarks of some older SCSI hardware.

Compatibility

Tested with Linux (current), Apple Macintosh System 7.5.3 on LC-III, and LC-475 hardware.

Users have reported success on these systems:

  • Mac II running System 6.0.8
  • Mac SE/30
  • Roland JS-30 Sampler
  • Akai S1000, S3200, S3000XL, MPC 2000XL, DPS 12
  • EMU Emulator E4X with EOS 3.00b and E6400 (classic) with Eos 4.01
  • Ensoniq ASR-X, ASR-10 (from v3.4, 2GB size limit)
  • Kurzweil K2000R with v3.87 firmware.
  • HP 16601A logic analyzer
  • Apple IIgs using Apple II High Speed SCSI controller card (from v3.3)

There are compatibility problems with the Akai MPC3000 with multi-sector transfers enabled.

Files

Firmware update utility and configuration tool download.

These files are currently available for Windows and Linux (64bit, requires the libudev1 package).

The schematics, pcb layout, and source code is managed under the git version control system. A copy of all sources can be obtained via the command:

git clone --recursive git://www.codesrc.com/git/SCSI2SD

Alternatively, the git sources can be viewed using your web browser by clicking here.

The schematics and PCB layout files can be viewed/edited with the free gEDA tools. For those without access to gEDA, I've exported the content as PDF:

The software is built using the Cypress PSoC Creator IDE.

Howto

Alternative Open SCSI Projects

  • AJ's alternative implementation. AJ and I originally had a competition to design and build a SCSI device to boot an old Mac LCIII. The deadline for that competition has long-since expired without a winner, but we have both continued to progress our designs.
  • S2I (was: SCSI2IDE)
  • AVR based SCSI RAM disk

Old

For historical project information see SCSI2SD old