Vintage Seagate ST-157R 49MB RLL hard drive.
Powerful SMS/OMTI-8257 RLL controller with upgraded B3 BIOS.
Early, Classic Seagate hard drive.
Suitable for a collection or period-accurate early 90\'s retro system.
SN: 1566457

• Drive originally purchased directly from Seagate distribution in 1990 for our PC production.
• Omti controller purchased directly from SMS/OMTi on Feb 16, 1990 for our PC production.
• Was removed by our service dept decades ago during a routine upgrade and has been in protected storage since.
• These drives have had relatively little use — we had an aggressive upgrade program so most drives were upgraded after only 12 to 24 months. The removed drives have been stored undisturbed for decades.
• Full true low-level format performed, both to remove customer data, and also to refresh the format as is needed for early ST412 drives.
• Factory bad sector map entries were entered and locked out during low level format.
• Single large partition created.
• MS-DOS 6.22 freshly installed.
• Scandisk full surface scan shows zero bad clusters (see screenshot).
• Chkdsk shows zero bad sectors (see screenshot).
• All formating and tested was performed using the included OMTI-8257 RLL controller and cables so you know everything works together perfectly.
• Should boot right up in any compatible system.
• To boot, BIOS drive parameters must be set as configured — CHS: 615/6/26.
  • Write precomp = 616 (none); landing zone = 616 (none, auto-park).
• Includes drive control and data cables (controller accepts standard floppy cable).
  
• If you want to use a different controller, you\'re on your own... will need a new low-level format and re-testing, but you know that this drive is intrinsically good (please see discussion below).
• Clean, very good physical and cosmetic condition.

You will receive exactly the item 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:
• Sold with 30 Day Warranty — If the drive fails or a serious defect not described in the listing is found within 30 days of purchase, I will stand behind the product.
• Please contact me with details of any issue so we can resolve the problem or work out an appropriate solution.
• I will provide a reasonable amount of technical assistance if you have questions concerning the configuration or proper use of the item.

Discussion:
• The earliest hard drives required a true controller. These early controllers actually \'controlled\' the heads on the hard drive, positioning the heads to the correct track and activating the correct head to read the requested data. In the low-level formatting process, the controller lays down the tracks and sector marks. Different controllers do this slightly differently so that one controller probably cannot read the tracks written by a different model controller. It\'s safe to assume that if you change the controller model, you will need to perform a new low-level format with the different controller.
• One benefit of RLL over MFM not often considered is that not only do you get 50% greater capacity on the same media, but the resulting data transfer rate is also 50% faster! This is so because 50% more data is read and transferred within the same time.
• To clear up another point of confusion: The first controllers were MFM, then newer RLL encoding technology achieved 50% greater capacity on the same media. MFM controllers work fine with RLL drives, but with 1/3 lower capacity. RLL controllers \'probably\' work with drives designed for MFM and increase the capacity by 50%. The magnetic recording is the same, but RLL utilizes a more efficient encoding scheme to pack 50% more data on the same track. MFM controllers always use MFM encoding, and RLL controller always use RLL encoding because the encoding schemes are hard-coded into the controller circuitry, therefore MFM and RLL controllers are not interchangeable (an MFM controller cannot function as an RLL controller, and vice versa). Keep in mind that changing the controller requires a new low-level format.
• Most people are familiar with IDE, which is an improved design — IDE (Integrated Device Electronics), as its name says, integrates the controller within the circuitry of the hard drive itself so it remains integral to the drive. IDE \'controllers\' are not true controllers, but are simple adapters which connect the controller embedded in the IDE drive to the computer bus. The IDE interface is a defined standard, so IDE drives and adapters are freely interchangeable. Most IDE drive use RLL encoding and utilize zone-bit encoding to further increase capacity by varying the number of sectors on the outer vs inner tracks.