content_image/977894.jpg content_image/977895.jpg
The components of the 3850 were new data cartridges. The data cartridges were circular cylinders, 2 inches in diameter and 4 inches long, each holding a spool holding 770 inches of tape. Cartridges were stored in a two-dimensional array of bins, which were hexagonal, rather than square, to save space and, for the first time, were automatically accessed through a robot (accessor), shown in Figure 1-13. 

## 1.2.8 IBM 3480 

<img src='content_image/977894.jpg'>

The second generation of IBM magnetic media and the first one to use an enclosed cartridge containing ‰-inch tape, the IBM 3480 Magnetic Tape Subsystem was announced on 22 March 1984, shown in Figure 1-14. The tape was stored in a now-familiar cartridge, which was smaller, more robust, and easier to handle than tape reels. The cartridge capacity was 200 MB, and the channel data rate was 3 MBps, writing 18 tracks in one direction. 

## 1.2.9 IBM 3490 

<img src='content_image/977895.jpg'>

The IBM 3490 replaced the IBM 3480 tape technology and used the same tape cartridge media. With a tape capacity of 800 MB uncompacted (2.4 GB compressed assuming 3:1 compression ratio) and a channel data rate of 3 MBps, the IBM 3490E increased the capacity of the 3480 four-fold. It used a double-length tape and wrote data in both directions: 18 tracks to the end of tape and 18 tracks back to the start of the tape. 

