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Macintosh SCSI hard drive replacements

In the past few years numerous options have been created to replace old failing SCSI hard drives so I’ve decided to create this post so I can keep track of those options and the features they provide. My focus is on using them with Macintosh computers from the 80s and 90s but most also support any device that uses a SCSI hard drive (e.g. the BlueSCSI option provides an extensive list)

Feature summary (2024/03/24)

Note: the majority of these solutions use SD or MicroSD cards for storage therefore I decided not to include storage type as a column. There is a SCSI to Compact Flash solution, but it is more targeted towards industrial solutions and is priced accordingly.

NameRead/Write
MB/sec		ImagesNetworkExtras
BlueSCSI v2
(RP2040)		9.5 / 7.3HD, FD, MO, RE, TP
CD (ISO, BIN, TOAST)		YesUI, CD Switcher, Clone, ROM Disk
MacSD3.2 / 2.5
(at 57Mhz)		RAW, HD, VOL, FD (DiskCopy 4.2)
CD (ISO, BIN, TOC, CUE)		NoUI, MIDI, Terminal, Fan Control
PiSCSI / RaSCSI?HD
CD, MO		YesUI, Video Out
SCSI2SD V5.x2.6 / 2.3RAWNoNone
SCSI2SD V610 / ?RAWNoNone
ZuluSCSI v1.23.5 / 2RAW (v1.2), HD, CD, FD, MO, RE, TP
CD (ISO, BIN)		NoUSB Mass Storage Mode
ZuluSCSI RP20409.5 / 6HD, CD, FD, MO, RE, TP
CD (ISO, BIN)		YesClone, USB Mass Storage Mode
Drive Image (HD), CD-ROM (CD), Floppy (FD), Magneto Optical (MO), Removable (RE), Sequential Tape (TP), Volume Image (VOL), No files (RAW)
Figure 1: Contents of a “drive image”

For the Read/Write speed these are the theoretical maximums and depend on the maximum transfer speed of the Macintosh System you are using, and the quality of your SD card.

  • CD: A CD-ROM image file that contains a copy of either a CD-ROMs data track (ISO), or a binary copy of the entire CD (BIN). BIN support usually means that the device can handle mixed mode CD-ROM images, e.g. an image of a CD that contained both data and audio tracks, see the device’s description for more details.
  • FD: A Floppy Disk image file that contains a binary copy of a floppy disk, these files are 400KB (single sided, single density, SS), 800KB (double sided, single density, DS) or 1440KB (double sided, double density, HD). If the FD image is not one of these sizes it is likely a DiskCopy 4.2 image, which you can convert to a regular FD image by removing the header information from the file.
  • HD: A Hard Drive file or Drive Image file contains a binary copy of the complete contents of an initialized drive including the drive’s boot driver and partition information in the first 48KB of the image file and one or more partitions/volumes.
  • MO: Magneto Optical Image file, I’ve never tested this, so I’m not sure how these would differ from a HD image.
  • TP: Sequential Tape Image file, I’ve never tested this, so not sure how it would work.
  • VOL: A Volume or Partition Image file (I’ve seen the term volume and partition used interchangeably) contains a binary copy of a single Macintosh volume/partition from a hard drive or removable drive.  These images lack both the boot sector and partition map. When most emulators refer to a hard drive file they are typically referring to a volume/partition image NOT a drive file.
  • RAW: unlike the above options where the images files stored as files on an FAT32 or exFAT formatted SD card, RAW indicates that the device is treating the entire SD card or part of the SD card as if it is the actual hard drive and directly reading and writing to a specific sector range on the SD card. E.g. for SCSI2SD you can specify up to 4 drives on a single card by specifying the starting sector and length of these drives using SCSI2SD’s setup utility. For MacSD you can create up to 4 partitions on a single SD card with the 3 partitions being treated as a physical drive, and one FAT32 partition for configuration settings (macsd.ini).

I have bootable copies of CD-ROM, FD, HD, and VOL image files on my downloads page.

BlueSCSI v2

MacSD

  • Main website: https://macsd.com/. I also wrote a guide on how to use the MacSD’s collection feature
  • Versions: Internal (50 pin IDC ribbon)
  • Storage: SD.
  • Format: FAT32 (your image files must be 4GB or less if you format your SD card using FAT32) unless you use the Partition feature (see section 6 of the manual).
  • Images:
    • DiskCopy 4.2 images: are supported, the MacSD treats these as volume images.
    • ISO CD-ROM images: 2048-byte sector ISO images used for single data track CDs,
    • BIN CD-ROM images: 2352 byte per sector BIN images, the TOC or CUE file must named the same as the BIN file. Supports BIN/MODE1, redbook/audio and mixed-mode disc images.
    • Volume Images: The support for Volume Images is unique to the MacSD at the moment. The MacSD can dynamically create a drive image from a collection of Volume files (section 8 of the manual). This feature is the reason why I use the MacSD in my Macintosh LC475. It allows me to have more than 2 ProDOS partitions for a single drive for use with my Apple IIe Card.
  • Network: None.
  • Extras: provides a System 6.x + compatible application that lets you import .sit and other file directly off the SD card, supports MIDI over SCSI (section 9, driver), and supports CD audio out and CD audio in.

PiSCSI (replaces RaSCSI)

Fork of RaSCSI. PiSCSI is a virtual SCSI device emulator that runs on a Raspberry Pi. It is a two piece solution, with a hardware and software component. PiSCSI can emulate multiple SCSI devices concurrently, provides a control interface to attach / detach drives, as well as insert and eject removable media. Simply connect the PiSCSI interface board to your system, launch the PiSCSI software on the Raspberry Pi, and the virtual devices will be accessible as physical SCSI devices!

SCSI2SD

One of the first affordable options for a SCSI hard drive replacement.

ZuluSCSI v1.2

The ZuluSCSI v1.2 is still available, the ZuluSCSI v1.1 and ZuluSCSI Mini V1.0 have both been discontinued. ZuluSCSI was designed by Rabbit Hole Computing to replace the SCSI2SD when the parts for SCSI2SD became hard to obtain.

ZuluSCSI RP2040

Newer and faster version of the ZuluSCSI. There is a variation of the ZuluSCSI RP2040 called the SillyTinySCSI available from zigzagjoe on the 68kmla.org site.

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