When I worked at IBM my manager never made clear what was considered confidential and what I was allowed to say I did during my employment. I eventually called Employee Services Contact Centre but the person I spoke to didn't seem knowledgeable about the subject and sort of repeated back my question. She said I can't tell future employees what I did at IBM as it may be used against the company and I can't "reveal the process". So if I'm not allowed to say anything about what I did than how do I make it not look like a gapping whole in my resume/cover letter? Obviously they won't come after me if I give some indication (e.g. worked with technology) but I don't want to put filler on my resume. I mean just saying my job was IT gives away some information (since IBM technically does have great variation in employees e.g. medical doctors).
Since my job was IT related, in particular I'd like to know if I can name the security products I configured or the operating systems I worked with. Also I know IBM is in competition with some of those operating systems and may be seen as an embarrassment if a resume has "At IBM I worked with [insert competitor company name here] products"