Fix typo in scsi2sd-config Makefile for building on Mac OSX
[SCSI2SD.git] / readme.txt
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1SCSI2SD, The SCSI Hard Drive Emulator for retro computing.
2
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3Traditional hard drives last 5 years*. Maybe, if you're luckly, you'll get 10
4years of service from a particular drive. The lubricants wear out, the spindles
5rust. SCSI2SD is a modern replacement for failed drives. It allows the use of
6vintage computer hardware long after their mechanical drives fail. The use of
7SD memory cards solves the problem of transferring data between the vintage
8computer and a modern PC (who still has access to a working floppy drive ?)
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090977f2 10*All statistics are made up.
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13Features
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15 In-built active terminator.
16 Can optional supply terminator power back to the SCSI bus
17 Emulates a non-removable hard drive for maximum compatibility.
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18 Firmware updatable over USB
19 Highly configurable over USB
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20 Selectable SCSI ID
21 Selectable parity support
22 Enable/disable Unit Attention Condition
23 Artificial limits on the SCSI disk size (eg. limit size to 4G to avoid OS bugs)
24
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26Technical Specifications
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28SCSI Interface
29 SCSI-2 Narrow 8-bit 50-pin connector. Supports asynchronous transfers only.
30SD Card Interface
31 Standard SDSC (1GB maximum size)
32 SDHC (32GB maximum size)
33 SDXC cards are untested. Donations welcome.
34 Communication is via the SPI protocol at 25MHz.
35Power
36 5V via standard molex drive connector.
37Dimensions
38 10cm x 10cm x 1.5cm
39 A 3D-printable bracket is in testing to suit a standard 3.5" hard disk bay.
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42Performance
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44As currently implemented:
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ad91a39f 46Sequential read: 424kb/sec Sequential write: 414kb/sec
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48Tested with a 16GB class 10 SD card, via the commands:
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50 # WRITE TEST
51 sudo dd bs=8192 count=100 if=/dev/zero of=/dev/sdX oflag=dsync
52
53 # READ TEST
54 sudo dd bs=8192 count=100 if=/dev/sdX of=/dev/null
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ad91a39f 56I am working on updating the SD card communication to use DMA, to allow simultaneous use of the SD and SCSI interfaces. I expect the performance to reach 1Mb/sec.
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59Compatibility
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61Tested with Linux (current), Apple Macintosh System 7.5.3 on LC-III, and LC-475
62hardware.
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