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A Trace Engine with Timestamp Clock Synchronized with an Atomic Clock

IP.com Disclosure Number: IPCOM000196938D
Publication Date: 2010-Jun-21
Document File: 3 page(s) / 143K

Publishing Venue

The IP.com Prior Art Database

Abstract

A trace engine is disclosed. The trace engine is a modified small computer interface (SCSI) Direct Access Storage Device (DASD) adapter. The trace engine is programmed to watch system bus for data being stored from any location into a range of addresses that are mapped to the trace engine. Due to the address mapping, the trace data is detected and captured by the trace engine.

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A Trace Engine with Timestamp Clock Synchronized with an Atomic Clock

Disclosed is a trace engine. The trace engine is a modified small computer interface (SCSI) Direct Access Storage Device (DASD) adapter. The trace engine is programmed to watch system bus for data being stored from any location into a range of addresses that are mapped to the trace engine. Due to the address mapping, the trace data is detected and captured by the trace engine.

The trace entry is begun upon receipt of 1st byte of data to a given address. The 1st bytes are ID and length, then length number of bytes.

Fig. 1 illustrates the working of the trace engine.

Figure 1

The trace engine buffers and timestamps the trace data. The timestamp is made using a timestamp clock with one microsecond resolution clock. The timestamp clock is synched to a global standard time such as GPS atomic time using a one second pulse accurate to < 1us. Therefore, the trace data from this trace engine will correlate perfectly with that from other trace engines that are synched to the same time. The

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buffered data is then formatted into trace entry format and stored in trace log in a battery backed RAM as shown in fig. 2. Since the RAM is battery backed, the trace log is not lost due to power loss as well.

Figure 2

From time to time the trace engine offloads the trace log to a hard drive. Since, the hard drive is used to offload the trace log, tr...