Check the listing for details. Texas Instruments TI Home Computer PHP1240 Disk Memory System Manual & Addendum. Condition: Very Good, Made in United States. Listed at 26.99 USD. This listing is for an original Texas Instruments Disk Memory System manual, Model No. PHP1240, for the Texas Instruments Home Computer series. It includes the addendum for Disk Memory System and Disk Memory Drive Manuals. This package includes information regarding the TI Disk Drive Controller Card and the Disk manager Solid State Software® Command Module, essential for connecting Disk Memory Drives (sold separately) to your computer. The manual is in good condition for its age, showing some signs of use but with all pages intact and readable. A valuable resource for collectors, enthusiasts, or anyone looking to maintain or troubleshoot their vintage TI-99/4A system. Please refer to photos for exact condition.