# full-height 5.25-inch drive > historical computer drive form factor **Wikidata**: [Q65037418](https://www.wikidata.org/wiki/Q65037418) **Source**: https://4ort.xyz/entity/full-height-5-25-inch-drive ## Summary The full-height 5.25-inch drive is a historical computer drive form factor standardized by the Small Form Factor Committee as SFF-8501. It serves as a physical specification for data storage devices, such as hard disk drives and tape drives, containing recording media alongside necessary electrical and mechanical components. While largely obsolete, it provided the physical dimensions for early storage technologies like the ST-506 hard disk drive. ## Key Facts * **Standardization:** The form factor is defined by standard **SFF-8501**, managed by the **Small Form Factor Committee**. * **Classification:** It is classified as a **drive form factor** and is a subclass of **drive** (a data storage device). * **Historical Context:** It is described as a **historical computer drive form factor**. * **Related Hardware:** The **ST-506**, a 5.25-inch hard disk drive introduced in **1980**, utilizes this form factor. * **Aliases:** The entity is also referred to by its standard identifier, **SFF-8501**. * **Media Types:** The form factor accommodates both **hard disk drives** (e.g., MFM drives) and **tape drives** (e.g., LTO-2). * **Visual Identification:** Full-height drives are visually distinct from smaller drives, such as the 2.5-inch form factor often shown beside them for comparison. ## FAQs ### Q: What is the full-height 5.25-inch drive standard called? A: The technical standard for this form factor is **SFF-8501**, which was established by the Small Form Factor Committee. ### Q: What types of drives used the full-height 5.25-inch form factor? A: This form factor was used for early **hard disk drives** (such as the 1980 ST-506 and MFM drives) and **tape drives** (such as full-height LTO-2 drives). ### Q: Is the full-height 5.25-inch drive still used today? A: No, it is considered a **historical computer drive form factor**. Modern storage typically utilizes much smaller form factors, such as 2.5-inch or 3.5-inch drives. ## Why It Matters The full-height 5.25-inch drive form factor represents a critical era in the physical evolution of computer hardware. Standardized as SFF-8501, it provided the physical constraints for early mass-market storage solutions, bridging the gap between large, room-sized storage units and the personal computer revolution. This form factor housed foundational technologies like the ST-506, which set the precedent for how data was recorded on rotating disks in microcomputers. By defining the dimensions for both hard disk and tape drives, this standard allowed manufacturers to design computer cases and storage bays with interchangeable components. Although it is now historical and visually massive compared to modern 2.5-inch drives, the SFF-8501 standard highlights the trend in computing toward miniaturization while maintaining the core definition of a drive as a device integrating recording media with electrical and mechanical operation. ## Notable For * **Standardization:** Being formally defined by the Small Form Factor Committee under the identifier SFF-8501. * **Historical Significance:** Serving as the form factor for the ST-506, the first 5.25-inch hard disk drive introduced in 1980. * **Versatility:** Accommodating distinct storage technologies, including rotating disk drives and magnetic tape drives. * **Size Definition:** Defining the "full-height" specification, which occupied a significant portion of early computer chassis space compared to half-height or modern drives. ## Body ### Definition and Classification The full-height 5.25-inch drive is a subclass of **drive**, defined in technical contexts as a data storage device. This device contains recording media—either internally or via a slot for removable media—along with the electrical or mechanical parts required to operate that media. Specifically, it falls under the classification of a **disk drive**, which records data on the surface of rotating disks. ### Technical Standards The form factor is governed by the **Small Form Factor Committee**. The specific standard documenting its dimensions and properties is **SFF-8501**. This standard ensures that drives classified as "full-height 5.25-inch" fit into corresponding drive bays and connect via interface standards compatible with the era, such as MFM (Modified Frequency Modulation) for hard drives. ### Hardware Implementations Historically, this form factor was utilized by several types of hardware: * **Hard Disk Drives (HDD):** Early HDDs, such as the **ST-506** (introduced in 1980) and subsequent MFM drives (e.g., 111 MB models), used this form factor. These drives stored data on rotating platters and were significantly larger than modern hard drives. * **Tape Drives:** The form factor was also adapted for linear tape-open (LTO) technologies, such as the **full-height 5.25" LTO-2 tape drive**, used for backup and archival storage. ### Visual Characteristics Physically, the drive is characterized by its 5.25-inch width and "full-height" vertical dimension. Visual comparisons often place these drives next to **2.5-inch drives** to illustrate the drastic reduction in storage form factor size over time.