...................is used for making magnetic recording tapes.

Answer

**Step-by-Step Solution:**

1. **Identify the Material**: The question asks for a specific polymer used in making magnetic recording tapes.

2. **Understanding the Polymer**: The polymer in question is known for its polyester linkage. This indicates that the polymer is formed through the reaction of a diacid and a diol.

3. **Identify the Specific Polymer**: The polymer that fits this description is Terephthalate, commonly known as Teriline or Decron.

4. **Monomer Units**: Terephthalate is synthesized from two monomer units:
- Terephthalic Acid (C6H4(COOH)2), which has a benzene ring with two carboxylic acid groups.
- Ethylene Glycol (C2H6O2), which is a simple diol with two hydroxyl (–OH) groups.

5. **Formation of the Polymer**: The polymerization occurs through a condensation reaction between Terephthalic Acid and Ethylene Glycol, resulting in the elimination of water (H2O) and the formation of the polyester linkage.

6. **Final Answer**: Therefore, the polymer used for making magnetic recording tapes is **Decron** or **Terephthalate**.

---