All finger-print based criminal history info is shared among the states and the federal government.
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In addition to what Ms. McCall said, it is routine for a prosecutor to run a nationwide criminal history check on people being charged with crimes.
The real question is: can these be used against you in a trial in California? Misdemeanor conduct can be used to demonstrate certain things under the rules of evidence. However, proving that will be a monster for the DA because he'll have to bring in the charging officer, etc etc. Moreover, your attorney will definitely require the DA to establish the elements of the misdemeanor in the other state to see if it matches a roughly comparable crime in California.
The most important thing for you to do right now is tell your attorney all about these misdemeanors in the other state, and don't fudge on the details. Your attorney will be able to tell you the effect of these misdemeanors (if any) on your prosecution for a felony in California.
Yes, the judge/prosecutor will be able to access the information regarding the priors. Therefore, you want to share all that information with your attorney so that the effect of these misdemeanors on you current prosecution can be assessed.