Evco RICS 4.30, Руководство пользователя

Страница: 31 / 104

19 RICS
Data storage
3.5 Occupation of space on the Hard Disk by recorded data
The Hard Disk space needed to record years of information depends on various factors, such as:
• Number of devices connected
• Sample frequency (recording)
• Types of devices connected
• Type of values sampled (temperature with a decimal point require more space than an integer value)
• Number of alarms that occur.
In general on a normal PC you can record years of data, even with the most extreme hypothesis.
Examples:
• An exaggerated estimate that considers 20 devices with 3 probes, decimal point management, and a sampling
frequency every 15 minutes with a certain number of alarms in the year comes to less than 2 megabytes per month
(24 hours a day). Therefore in this hypothesis the required space is around 20-25 megabytes per year. A CD-ROM
can therefore contain the equivalent of more than 30 yrs of samples. Note that compressing archived data (average
compression ratio 1:12-15 between original megabytes and compressed megabytes) substantially reduces the space
required. Therefore a CD-ROM could contain the equivalent of more than 400 yrs of compressed recordings.
• An even bigger hypothesis, considering 60 devices with 3 probes, decimal point management, sampling frequency
every minute and a certain number of alarms in the year will mean 80 megabytes per month (24 hours a day). In this
hypothesis, the space required becomes around 1,000 megabytes per year. Two CD-ROMs can contain the equiva-
lent of a year of uncompressed data.