Software management methods for automotive computing devices

• US 7,254,083 B2
• Filed: 05/27/2004
• Issued: 08/07/2007
• Est. Priority Date: 12/20/2000
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Beckert, Richard D., Drasnin, Sharon, Radko, Ronald Otto
• Primary Examiner(s): PEIKARI, BEHZAD
• Application Number:
  US10/856,010
• Publication Number:
  US 20040221093A1
• Time in Patent Office: 1,167 Days
• Field of Search: None
• US Class Current: 365/228
• CPC Class Codes: G06F 11/1441 Resetting or repowering
• CPC Class Codes: G06F 11/2015 Redundant power supplies power supply failure G06F1/30
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 12/1009 using page tables, e.g. page table structures
• CPC Class Codes: G06F 12/1027 using associative or pseudo-associative address translation means, e.g. translation look-aside buffer [TLB]
• CPC Class Codes: G06F 12/122 of the least frequently used [LFU] type, e.g. with individual count value
• CPC Class Codes: G06F 2212/2022 Flash memory

Abstract

Methods and systems for operating automotive computing devices are described. In one embodiment, a small amount of static RAM (SRAM) is incorporated into an automotive computing device. The SRAM is battery-backed to provide a non-volatile memory space in which critical data, e.g. the object store, can be maintained in the event of a power loss. Circuitry is provided to ensure that the SRAM receives back up power from the battery at appropriate times. Software manages the SRAM and the other storage assembly components and makes use of virtual paging or virtual addressing techniques to keep track of where various pages, including object store pages, are stored in the system. The software knows where all of the object store pages are located so that in the event of a power loss, the page locations are known and hence the pages can be used when power is restored. The SRAM is advantageously used to maintain so-called “dirty pages” or pages that have been written to so that these pages are not lost in the event of a power interruption. Additionally, the software can also provide an orderly means by which pages in the SRAM can be written out to flash memory thereby avoiding unnecessary flash write operations which, in turn, increases the lifetime of the flash memory.

Claims

1. In an automotive computing device, a method of booting the device comprising:

maintaining a copy of an object store in flash memory that is carried by the automotive computing device;

initiating a boot sequence of the automotive computing device;

during the boot sequence, paging only predetermined object store pages from the flash memory into RAM that is carried by the automotive computing device, said predetermined pages comprising less than all of the pages in the entire object store;

after the boot sequence, determining whether any additional object store pages are needed from the flash memory; and

paging any needed object store pages from the flash memory into the RAM.

2. The booting method of claim 1, wherein the RAM comprises DRAM.

3. The booting method of claim 1, wherein the RAM comprises SRAM.

4. The booting method of claim 1, wherein the RAM comprises battery-backed SRAM.