# NCR 53C9x

> family of SCSI interface ICs

**Wikidata**: [Q6953198](https://www.wikidata.org/wiki/Q6953198)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/NCR_53C9x)  
**Source**: https://4ort.xyz/entity/ncr-53c9x

## Summary
The NCR 53C9x is a family of SCSI interface integrated circuits (ICs) originally developed by NCR Corporation. It is designed as an application-specific integrated circuit (ASIC) and controller that implements the SCSI standard for interfacing with peripheral devices.

## Key Facts
- **Classification**: The NCR 53C9x is a model series and reference design for integrated circuits, specifically falling under the subclass of application-specific integrated circuits (ASICs) and controllers.
- **Developer**: The primary developer of the architecture is **NCR Corporation**, an American software, consulting, and technology company.
- **Function**: It serves as a SCSI interface controller, complying with the SCSI (Small Computer System Interface) standard.
- **Manufacturers**: While developed by NCR, the series was also manufactured by **Emulex**, **AMD** (Advanced Micro Devices), and **QLogic**.
- **Instance Type**: It is categorized as an integrated circuit model and a reference design.
- **Parent Class**: The device falls under the broad class of "controller," defined as a computing device that interfaces with a peripheral device.

## FAQs

### Q: What is the primary function of the NCR 53C9x?
A: The NCR 53C9x functions as a SCSI interface controller. It is an integrated circuit designed to manage data transfers between a computer system and peripheral devices using the SCSI standard.

### Q: Who developed and manufactured the NCR 53C9x?
A: The technology was developed by **NCR Corporation**. In addition to NCR, the integrated circuits were produced by other semiconductor manufacturers including **AMD**, **Emulex**, and **QLogic**.

### Q: What type of hardware component is the NCR 53C9x?
A: It is an Application-Specific Integrated Circuit (ASIC) classified as a controller. It is specifically a model series of SCSI interface chips.

## Why It Matters
The NCR 53C9x family holds significance in the history of computing hardware as a key enabling technology for the SCSI standard, which was the dominant interface for high-performance hard drives, scanners, and other peripherals throughout the 1990s and early 2000s. By providing a dedicated controller design (ASIC), this family of chips allowed computer manufacturers to integrate reliable SCSI connectivity into servers and workstations.

Its classification as a "reference design" indicates that the NCR 53C9x was likely used as a standard blueprint that was licensed or second-sourced by other major semiconductor companies like AMD and QLogic. This widespread adoption by multiple manufacturers helped standardize SCSI implementation across the industry, ensuring compatibility and reducing costs for system builders.

## Notable For
- **Multi-Vendor Manufacturing**: Unlike many chips produced solely by their creator, the 53C9x was manufactured by four distinct entities: NCR, AMD, Emulex, and QLogic.
- **Reference Design**: It is explicitly categorized as a reference design, suggesting it served as an industry standard template for SCSI controller implementation.
- **ASIC Architecture**: It represents an early application of Application-Specific Integrated Circuits for standard interface control.
- **NCR Engineering**: It stands as a notable hardware product from NCR Corporation, a company historically rooted in cash registers but heavily involved in computer hardware and semiconductor technology.

## Body

### Technical Classification
The NCR 53C9x is structured as a **model series** of integrated circuits. It falls under the broader category of **controllers**—devices used to interface with peripheral hardware. Specifically, it is subclassed as an **application-specific integrated circuit (ASIC)**, indicating it was custom-designed for the specific purpose of managing SCSI communications rather than for general-purpose computing.

### Development and Production
The architecture was created by **NCR Corporation** (formerly the National Cash Register Company), a major American technology firm founded in 1884. While NCR is credited as the developer, the physical production of the 53C9x series involved a multi-manufacturer ecosystem. The chips were produced by:
*   NCR Corporation
*   Emulex
*   AMD (Advanced Micro Devices)
*   QLogic

### Compliance and Implementation
The primary technical specification of the NCR 53C9x is its compliance with the **SCSI** (Small Computer System Interface) standard. As a SCSI interface IC, the series functions as the necessary hardware bridge allowing a host system to send and receive commands and data to external storage and peripherals.

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