Vintage Seagate ST-157R-1 49MB RLL hard drive.
Perfect for a period-accurate retro build, or for a museum collection.
This is the FAST 28ms version identified by the "-1" in the model number (-0 is 40ms).
28ms, 3600rpm, 7.5Mbps xfer rate, auto-park.
Early, Classic Seagate hard drive.
Suitable for a collection or period-accurate early 90's retro system.
Paired with the powerful SMS/Omti 8257 16-bit ISA controller with updated B3 BIOS.
Seagate ST157R sn.1924589
OMTi 8257 sn.2997

• Drive originally purchased directly from Seagate distribution in 1990 for our PC production.
  • This drive had very little use, was upgraded within months to a larger drive as technology was rapidly advancing.
• Controller originally purchased directly from SMS/OMTi on Feb 22, 1990 for our PC production.
• Both were removed by our service dept decades ago during routine upgrades and have been in protected storage since.
• Great choice for a 90's period-accurate retro system.
• This is a nice size because it is within certain capacity limits of early vintage BIOS and O/S
• The following procedures have been performed:
  • Full low-level format using original Seagate supplied utilities.
  • Full surface scan using original Seagate supplied utilities.
  • Full deep surface scan using SpinRite6 to discover and lock out any additional surface defects.
  • Fresh install of MS-DOS 6.22 using Microsoft officially provided installation media.
  • Full clean install of MS-DOS 6.22 with no additions or modifications.
  • Boot to installed MS-DOS 6.22 and run SCANDISK, save results to disk (see screen capture).
  • Run CHKDSK for HDD stats (see screen capture).
  • NOTE: Nearly all hard drives have a few bad sectors which are visible in very early drives such as this. Later IDE drives also have bad sectors, but they are hidden. Even current SATA drives have bad sectors which are hidden.
• Should boot directly to MS-DOS 6.22 in any compatible system.
  • Motherboard BIOS must have drive type 47 (user defined) because the standard AT BIOS table will not have RLL sector counts.
  • The hard drive parameters must be set correctly in the BIOS or the drive will not boot and could become corrupted.
  • The correct parameters for this drive are: Cylinders=615, Heads=6, Sectors=26, Precomp= none (65535), Landing Zone= autopark (65535).
• A working drive and controller pair can be moved together as a subsystem and should boot right up in any properly working motherboard if the BIOS drive parameters are set correctly.
  • DOS itself is system agnostic and can be freely moved between different systems.
• Or, install anything on it you want, different O/S or whatever.
  • However, drive is only warrantied to boot as configured so make sure to test that first.
  • During low level formatting, an MFM or RLL controller writes positioning and sector marks so it can find its way around the disc surfaces.
  • Changing the controller always requires a new low level format because each controller lays out sector marks slightly differently. A different controller may give different results.
• It is certainly capable of being connected to a different controller and reformatted, but that introduces many variables — not only functionality of the different hardware, but also the skill and knowledge of the technician. So once you deviate from the supplied configuration the warranty will be void and you're on your own. If you know what you're doing and have good equipment, you should succeed.
• If you choose to reconfigure, contact me and I will try to help .
• Control and Data cables, plus universal FDD cable (3.5 & 5.25" at both connections) are included.
• All low-level formatting, testing, formatting, and O/S installation was done with the exact controller and cables provided, so you know it works.
• Great for any retro system or collection.
• Clean, excellent cosmetic condition.

You will receive exactly the items you see in the photos.

Shipped via USPS with full tracking from a USPS regional SCF (Sectional Center Facility) so delivery anywhere within the U.S. is only a few days away (excluding the occasional USPS misdirect).

RETURNS:
• Please contact me with details of any issue FIRST so we can resolve the problem or work out an appropriate solution.
• I have decades of experience troubleshooting problems with vintage components.
• I will provide a reasonable amount of technical assistance if you have questions concerning the configuration or proper use of the item.